diff --git a/Source/Core/Core/Config/MainSettings.cpp b/Source/Core/Core/Config/MainSettings.cpp
index c9cd0333a9..23a458f2b9 100644
--- a/Source/Core/Core/Config/MainSettings.cpp
+++ b/Source/Core/Core/Config/MainSettings.cpp
@@ -190,6 +190,8 @@ const Info<bool> MAIN_WIIMOTE_CONTINUOUS_SCANNING{
 const Info<bool> MAIN_WIIMOTE_ENABLE_SPEAKER{{System::Main, "Core", "WiimoteEnableSpeaker"}, false};
 const Info<bool> MAIN_CONNECT_WIIMOTES_FOR_CONTROLLER_INTERFACE{
     {System::Main, "Core", "WiimoteControllerInterface"}, false};
+const Info<bool> MAIN_USE_GC_ADAPTER_FOR_CONTROLLER_INTERFACE{
+    {System::Main, "Core", "GCAdapterControllerInterface"}, false};
 const Info<bool> MAIN_MMU{{System::Main, "Core", "MMU"}, false};
 const Info<bool> MAIN_PAUSE_ON_PANIC{{System::Main, "Core", "PauseOnPanic"}, false};
 const Info<int> MAIN_BB_DUMP_PORT{{System::Main, "Core", "BBDumpPort"}, -1};
diff --git a/Source/Core/Core/Config/MainSettings.h b/Source/Core/Core/Config/MainSettings.h
index b6e8f966c7..17a8cfb8fe 100644
--- a/Source/Core/Core/Config/MainSettings.h
+++ b/Source/Core/Core/Config/MainSettings.h
@@ -108,6 +108,7 @@ extern const Info<bool> MAIN_WII_KEYBOARD;
 extern const Info<bool> MAIN_WIIMOTE_CONTINUOUS_SCANNING;
 extern const Info<bool> MAIN_WIIMOTE_ENABLE_SPEAKER;
 extern const Info<bool> MAIN_CONNECT_WIIMOTES_FOR_CONTROLLER_INTERFACE;
+extern const Info<bool> MAIN_USE_GC_ADAPTER_FOR_CONTROLLER_INTERFACE;
 extern const Info<bool> MAIN_MMU;
 extern const Info<bool> MAIN_PAUSE_ON_PANIC;
 extern const Info<int> MAIN_BB_DUMP_PORT;
diff --git a/Source/Core/DolphinLib.props b/Source/Core/DolphinLib.props
index a61f0d822a..30bc9b00cb 100644
--- a/Source/Core/DolphinLib.props
+++ b/Source/Core/DolphinLib.props
@@ -532,6 +532,7 @@
     <ClInclude Include="InputCommon\ControllerInterface\MappingCommon.h" />
     <ClInclude Include="InputCommon\ControllerInterface\WGInput\WGInput.h" />
     <ClInclude Include="InputCommon\ControllerInterface\Wiimote\WiimoteController.h" />
+    <ClInclude Include="InputCommon\ControllerInterface\GCAdapter\GCAdapter.h" />
     <ClInclude Include="InputCommon\ControllerInterface\Win32\Win32.h" />
     <ClInclude Include="InputCommon\ControllerInterface\XInput\XInput.h" />
     <ClInclude Include="InputCommon\ControllerInterface\SDL\SDL.h" />
@@ -1193,6 +1194,7 @@
     <ClCompile Include="InputCommon\ControllerInterface\MappingCommon.cpp" />
     <ClCompile Include="InputCommon\ControllerInterface\WGInput\WGInput.cpp" />
     <ClCompile Include="InputCommon\ControllerInterface\Wiimote\WiimoteController.cpp" />
+    <ClCompile Include="InputCommon\ControllerInterface\GCAdapter\GCAdapter.cpp" />
     <ClCompile Include="InputCommon\ControllerInterface\Win32\Win32.cpp" />
     <ClCompile Include="InputCommon\ControllerInterface\XInput\XInput.cpp" />
     <ClCompile Include="InputCommon\ControllerInterface\SDL\SDL.cpp" />
diff --git a/Source/Core/DolphinQt/Config/GamecubeControllersWidget.cpp b/Source/Core/DolphinQt/Config/GamecubeControllersWidget.cpp
index d548724c7e..05956f5820 100644
--- a/Source/Core/DolphinQt/Config/GamecubeControllersWidget.cpp
+++ b/Source/Core/DolphinQt/Config/GamecubeControllersWidget.cpp
@@ -3,6 +3,7 @@
 
 #include "DolphinQt/Config/GamecubeControllersWidget.h"
 
+#include <QCheckBox>
 #include <QComboBox>
 #include <QGridLayout>
 #include <QGroupBox>
@@ -95,6 +96,10 @@ void GamecubeControllersWidget::CreateLayout()
     m_gc_layout->addWidget(gc_box, controller_row, 1);
     m_gc_layout->addWidget(gc_button, controller_row, 2);
   }
+
+  m_gcpad_ciface = new QCheckBox(tr("Use Wii-U Adapter for Emulated Controllers"));
+  m_gc_layout->addWidget(m_gcpad_ciface, m_gc_layout->rowCount(), 0, 1, -1);
+
   m_gc_box->setLayout(m_gc_layout);
 
   auto* layout = new QVBoxLayout;
@@ -114,6 +119,8 @@ void GamecubeControllersWidget::ConnectWidgets()
     });
     connect(m_gc_buttons[i], &QPushButton::clicked, this, [this, i] { OnGCPadConfigure(i); });
   }
+
+  connect(m_gcpad_ciface, &QCheckBox::toggled, this, &GamecubeControllersWidget::SaveSettings);
 }
 
 void GamecubeControllersWidget::OnGCTypeChanged(size_t index)
@@ -184,6 +191,9 @@ void GamecubeControllersWidget::LoadSettings(Core::State state)
       OnGCTypeChanged(i);
     }
   }
+
+  SignalBlocking(m_gcpad_ciface)
+      ->setChecked(Config::Get(Config::MAIN_USE_GC_ADAPTER_FOR_CONTROLLER_INTERFACE));
 }
 
 void GamecubeControllersWidget::SaveSettings()
@@ -203,11 +213,15 @@ void GamecubeControllersWidget::SaveSettings()
         system.GetSerialInterface().ChangeDevice(si_device, static_cast<s32>(i));
       }
     }
+
+    Config::SetBaseOrCurrent(Config::MAIN_USE_GC_ADAPTER_FOR_CONTROLLER_INTERFACE,
+                             m_gcpad_ciface->isChecked());
   }
+
+  SConfig::GetInstance().SaveSettings();
+
   if (GCAdapter::UseAdapter())
     GCAdapter::StartScanThread();
   else
     GCAdapter::StopScanThread();
-
-  SConfig::GetInstance().SaveSettings();
 }
diff --git a/Source/Core/DolphinQt/Config/GamecubeControllersWidget.h b/Source/Core/DolphinQt/Config/GamecubeControllersWidget.h
index f4d1b69f60..385ab7c947 100644
--- a/Source/Core/DolphinQt/Config/GamecubeControllersWidget.h
+++ b/Source/Core/DolphinQt/Config/GamecubeControllersWidget.h
@@ -7,6 +7,7 @@
 
 #include <array>
 
+class QCheckBox;
 class QComboBox;
 class QHBoxLayout;
 class QGridLayout;
@@ -40,4 +41,5 @@ private:
   std::array<QComboBox*, 4> m_gc_controller_boxes;
   std::array<QPushButton*, 4> m_gc_buttons;
   std::array<QHBoxLayout*, 4> m_gc_groups;
+  QCheckBox* m_gcpad_ciface;
 };
diff --git a/Source/Core/InputCommon/CMakeLists.txt b/Source/Core/InputCommon/CMakeLists.txt
index ee144e32f4..38455f86ce 100644
--- a/Source/Core/InputCommon/CMakeLists.txt
+++ b/Source/Core/InputCommon/CMakeLists.txt
@@ -64,6 +64,8 @@ add_library(inputcommon
   ControllerInterface/MappingCommon.h
   ControllerInterface/Wiimote/WiimoteController.cpp
   ControllerInterface/Wiimote/WiimoteController.h
+  ControllerInterface/GCAdapter/GCAdapter.cpp
+  ControllerInterface/GCAdapter/GCAdapter.h
   ControlReference/ControlReference.cpp
   ControlReference/ControlReference.h
   ControlReference/ExpressionParser.cpp
diff --git a/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp b/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
index 769e6c5f0e..32a03a1f86 100644
--- a/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
@@ -8,6 +8,7 @@
 #include "Common/Assert.h"
 #include "Common/Logging/Log.h"
 #include "Core/HW/WiimoteReal/WiimoteReal.h"
+#include "InputCommon/ControllerInterface/GCAdapter/GCAdapter.h"
 
 #ifdef CIFACE_USE_WIN32
 #include "InputCommon/ControllerInterface/Win32/Win32.h"
@@ -86,6 +87,9 @@ void ControllerInterface::Initialize(const WindowSystemInfo& wsi)
   m_input_backends.emplace_back(ciface::SteamDeck::CreateInputBackend(this));
 #endif
 
+  // TODO: obey Config::Get(Config::MAIN_USE_GC_ADAPTER_FOR_CONTROLLER_INTERFACE)
+  m_input_backends.emplace_back(ciface::GCAdapter::CreateInputBackend(this));
+
   // Don't allow backends to add devices before the first RefreshDevices() as they will be cleaned
   // there. Or they'd end up waiting on the devices mutex if populated from another thread.
   m_is_init = true;
diff --git a/Source/Core/InputCommon/ControllerInterface/GCAdapter/GCAdapter.cpp b/Source/Core/InputCommon/ControllerInterface/GCAdapter/GCAdapter.cpp
new file mode 100644
index 0000000000..8d66e61892
--- /dev/null
+++ b/Source/Core/InputCommon/ControllerInterface/GCAdapter/GCAdapter.cpp
@@ -0,0 +1,258 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "InputCommon/ControllerInterface/GCAdapter/GCAdapter.h"
+
+#include <array>
+
+#include "Core/HW/SI/SI.h"
+#include "InputCommon/ControllerInterface/ControllerInterface.h"
+#include "InputCommon/GCAdapter.h"
+#include "InputCommon/GCPadStatus.h"
+
+// TODO: namespace name matching the one in InputCommon/GCAdapter.h is annoying
+namespace ciface::GCAdapter
+{
+constexpr auto SOURCE_NAME = "GCAdapter";
+
+class GCController;
+
+class InputBackend final : public ciface::InputBackend
+{
+public:
+  InputBackend(ControllerInterface* controller_interface);
+  void PopulateDevices() override;
+  void UpdateInput(std::vector<std::weak_ptr<ciface::Core::Device>>& devices_to_remove) override;
+
+private:
+  std::array<std::weak_ptr<GCController>, SerialInterface::MAX_SI_CHANNELS> m_devices;
+};
+
+std::unique_ptr<ciface::InputBackend> CreateInputBackend(ControllerInterface* controller_interface)
+{
+  return std::make_unique<InputBackend>(controller_interface);
+}
+
+struct DigitalInputProps
+{
+  u16 value;
+  const char* name;
+};
+
+constexpr DigitalInputProps digital_inputs[] = {
+    {PAD_BUTTON_UP, "Up"},
+    {PAD_BUTTON_DOWN, "Down"},
+    {PAD_BUTTON_LEFT, "Left"},
+    {PAD_BUTTON_RIGHT, "Right"},
+    {PAD_BUTTON_A, "A"},
+    {PAD_BUTTON_B, "B"},
+    {PAD_BUTTON_X, "X"},
+    {PAD_BUTTON_Y, "Y"},
+    {PAD_TRIGGER_Z, "Z"},
+    {PAD_TRIGGER_L, "L"},
+    {PAD_TRIGGER_R, "R"},
+    // TODO: "START" or "Start"?
+    {PAD_BUTTON_START, "Start"},
+};
+
+struct AnalogInputProps
+{
+  u8 GCPadStatus::*ptr;
+  const char* name;
+};
+
+constexpr AnalogInputProps stick_inputs[] = {
+    {&GCPadStatus::stickX, "Main X"},
+    {&GCPadStatus::stickY, "Main Y"},
+    {&GCPadStatus::substickX, "C X"},
+    {&GCPadStatus::substickY, "C Y"},
+};
+
+constexpr AnalogInputProps trigger_inputs[] = {
+    {&GCPadStatus::triggerLeft, "L-Analog"},
+    {&GCPadStatus::triggerRight, "R-Analog"},
+};
+
+class DigitalInput : public Core::Device::Input
+{
+public:
+  DigitalInput(const u16* button_state, u32 index) : m_button_state{*button_state}, m_index{index}
+  {
+  }
+
+  std::string GetName() const override { return digital_inputs[m_index].name; }
+
+  ControlState GetState() const override
+  {
+    return (digital_inputs[m_index].value & m_button_state) != 0;
+  }
+
+private:
+  const u16& m_button_state;
+  const u32 m_index;
+};
+
+class AnalogInput : public Core::Device::Input
+{
+public:
+  AnalogInput(const GCPadStatus* pad_status, const AnalogInputProps& props, u8 neutral_value,
+              s32 range)
+      : m_base_name{props.name}, m_neutral_value{neutral_value}, m_range{range},
+        m_state{pad_status->*props.ptr}
+  {
+  }
+
+  ControlState GetState() const override
+  {
+    return ControlState(m_state - m_neutral_value) / m_range;
+  }
+
+protected:
+  const char* const m_base_name;
+  const u8 m_neutral_value;
+  const s32 m_range;
+
+private:
+  const u8& m_state;
+};
+
+class StickInput : public AnalogInput
+{
+public:
+  using AnalogInput::AnalogInput;
+
+  std::string GetName() const override
+  {
+    return std::string(m_base_name) + (m_range > 0 ? '+' : '-');
+  }
+};
+
+class TriggerInput : public AnalogInput
+{
+public:
+  using AnalogInput::AnalogInput;
+
+  std::string GetName() const override { return m_base_name; }
+};
+
+class Motor : public Core::Device::Output
+{
+public:
+  Motor(u32 index) : m_index{index} {}
+
+  void SetState(ControlState value) override
+  {
+    const bool new_state = std::lround(value);
+
+    if (new_state == m_last_state)
+      return;
+
+    m_last_state = new_state;
+
+    ::GCAdapter::Output(m_index, new_state);
+  }
+
+  std::string GetName() const override { return "Motor"; }
+
+private:
+  u32 m_index;
+  bool m_last_state = false;
+};
+
+class GCController : public Core::Device
+{
+public:
+  GCController(u32 index) : m_index{index}
+  {
+    // Add buttons.
+    for (u32 i = 0; i != std::size(digital_inputs); ++i)
+      AddInput(new DigitalInput{&m_pad_status.button, i});
+
+    // TODO: use origin values.
+    const auto origin = ::GCAdapter::GetOrigin(index);
+
+    // Add sticks.
+    for (auto& props : stick_inputs)
+    {
+      // Add separate -/+ inputs.
+      AddInput(new StickInput{&m_pad_status, props, GCPadStatus::MAIN_STICK_CENTER_X,
+                              -GCPadStatus::MAIN_STICK_RADIUS});
+      AddInput(new StickInput{&m_pad_status, props, GCPadStatus::MAIN_STICK_CENTER_X,
+                              GCPadStatus::MAIN_STICK_RADIUS});
+    }
+
+    // Add triggers.
+    for (auto& props : trigger_inputs)
+      AddInput(new TriggerInput{&m_pad_status, props, 0, std::numeric_limits<u8>::max()});
+
+    // Rumble.
+    AddOutput(new Motor{index});
+  }
+
+  std::optional<int> GetPreferredId() const override { return m_index; }
+
+  std::string GetName() const override
+  {
+    // TODO: name?
+    return "GCPad";
+  }
+
+  std::string GetSource() const override { return SOURCE_NAME; }
+
+  int GetSortPriority() const override { return -3; }
+
+  Core::DeviceRemoval UpdateInput() override
+  {
+    m_pad_status = ::GCAdapter::PeekInput(m_index);
+    return Core::DeviceRemoval::Keep;
+  }
+
+private:
+  GCPadStatus m_pad_status;
+  const u32 m_index;
+};
+
+InputBackend::InputBackend(ControllerInterface* controller_interface)
+    : ciface::InputBackend(controller_interface)
+{
+  ::GCAdapter::Init();
+}
+
+void InputBackend::PopulateDevices()
+{
+  for (int i = 0; i != SerialInterface::MAX_SI_CHANNELS; ++i)
+  {
+    if (::GCAdapter::DeviceConnected(i))
+    {
+      auto new_device = std::make_shared<GCController>(i);
+      m_devices[i] = new_device;
+      GetControllerInterface().AddDevice(std::move(new_device));
+    }
+  }
+}
+
+void InputBackend::UpdateInput(std::vector<std::weak_ptr<ciface::Core::Device>>& devices_to_remove)
+{
+  // "Hotplug" is handled here.
+  for (int i = 0; i != SerialInterface::MAX_SI_CHANNELS; ++i)
+  {
+    const bool is_device_connected = ::GCAdapter::DeviceConnected(i);
+    const auto device = m_devices[i].lock();
+
+    if (is_device_connected == (device != nullptr))
+      continue;
+
+    if (is_device_connected)
+    {
+      auto new_device = std::make_shared<GCController>(i);
+      m_devices[i] = new_device;
+      GetControllerInterface().AddDevice(std::move(new_device));
+    }
+    else
+    {
+      devices_to_remove.emplace_back(device);
+    }
+  }
+}
+
+}  // namespace ciface::GCAdapter
diff --git a/Source/Core/InputCommon/ControllerInterface/GCAdapter/GCAdapter.h b/Source/Core/InputCommon/ControllerInterface/GCAdapter/GCAdapter.h
new file mode 100644
index 0000000000..0dcb1a17fa
--- /dev/null
+++ b/Source/Core/InputCommon/ControllerInterface/GCAdapter/GCAdapter.h
@@ -0,0 +1,14 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <memory>
+
+#include "InputCommon/ControllerInterface/InputBackend.h"
+
+namespace ciface::GCAdapter
+{
+std::unique_ptr<ciface::InputBackend> CreateInputBackend(ControllerInterface* controller_interface);
+
+}  // namespace ciface::GCAdapter
diff --git a/Source/Core/InputCommon/GCAdapter.cpp b/Source/Core/InputCommon/GCAdapter.cpp
index 84b5022c99..6176b000d3 100644
--- a/Source/Core/InputCommon/GCAdapter.cpp
+++ b/Source/Core/InputCommon/GCAdapter.cpp
@@ -142,15 +142,6 @@ static Common::Event s_hotplug_event;
 
 static std::function<void(void)> s_detect_callback;
 
-#if defined(__FreeBSD__) && __FreeBSD__ >= 11
-static bool s_libusb_hotplug_enabled = true;
-#else
-static bool s_libusb_hotplug_enabled = false;
-#endif
-#if LIBUSB_API_HAS_HOTPLUG
-static libusb_hotplug_callback_handle s_hotplug_handle;
-#endif
-
 static std::unique_ptr<LibusbUtils::Context> s_libusb_context;
 
 static u8 s_endpoint_in = 0;
@@ -346,24 +337,32 @@ static void ScanThreadFunc()
 
 #if GCADAPTER_USE_LIBUSB_IMPLEMENTATION
 #if LIBUSB_API_HAS_HOTPLUG
-#ifndef __FreeBSD__
-  s_libusb_hotplug_enabled = libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) != 0;
+
+#if defined(__FreeBSD__)
+#if __FreeBSD__ >= 11
+  bool hotplug_enabled = true;
+#else
+  bool hotplug_enabled = false;
 #endif
-  if (s_libusb_hotplug_enabled)
+#else
+  bool hotplug_enabled = libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) != 0;
+#endif
+  libusb_hotplug_callback_handle hotplug_handle = {};
+  if (hotplug_enabled)
   {
     const int error = libusb_hotplug_register_callback(
         *s_libusb_context,
         (libusb_hotplug_event)(LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED |
                                LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT),
         LIBUSB_HOTPLUG_ENUMERATE, 0x057e, 0x0337, LIBUSB_HOTPLUG_MATCH_ANY, HotplugCallback,
-        nullptr, &s_hotplug_handle);
+        nullptr, &hotplug_handle);
     if (error == LIBUSB_SUCCESS)
     {
       NOTICE_LOG_FMT(CONTROLLERINTERFACE, "Using libUSB hotplug detection");
     }
     else
     {
-      s_libusb_hotplug_enabled = false;
+      hotplug_enabled = false;
       ERROR_LOG_FMT(CONTROLLERINTERFACE, "Failed to add libUSB hotplug detection callback: {}",
                     LibusbUtils::ErrorWrap(error));
     }
@@ -378,11 +377,17 @@ static void ScanThreadFunc()
       Setup();
     }
 
-    if (s_libusb_hotplug_enabled)
+    if (hotplug_enabled)
       s_hotplug_event.Wait();
     else
       Common::SleepCurrentThread(500);
   }
+
+#if LIBUSB_API_HAS_HOTPLUG
+  if (hotplug_enabled)
+    libusb_hotplug_deregister_callback(*s_libusb_context, hotplug_handle);
+#endif
+
 #elif GCADAPTER_USE_ANDROID_IMPLEMENTATION
   JNIEnv* const env = IDCache::GetEnvForThread();
 
@@ -410,12 +415,14 @@ void SetAdapterCallback(std::function<void(void)> func)
 
 static void RefreshConfig()
 {
-  s_is_adapter_wanted = false;
+  s_is_adapter_wanted = Config::Get(Config::MAIN_USE_GC_ADAPTER_FOR_CONTROLLER_INTERFACE);
 
   for (int i = 0; i < SerialInterface::MAX_SI_CHANNELS; ++i)
   {
     s_is_adapter_wanted |= Config::Get(Config::GetInfoForSIDevice(i)) ==
                            SerialInterface::SIDevices::SIDEVICE_WIIU_ADAPTER;
+
+    // TODO: ControllerInterface shouldn't obey this setting.
     s_config_rumble_enabled[i] = Config::Get(Config::GetInfoForAdapterRumble(i));
   }
 }
@@ -676,12 +683,6 @@ static void AddGCAdapter(libusb_device* device)
 void Shutdown()
 {
   StopScanThread();
-#if GCADAPTER_USE_LIBUSB_IMPLEMENTATION
-#if LIBUSB_API_HAS_HOTPLUG
-  if (s_libusb_context->IsValid() && s_libusb_hotplug_enabled)
-    libusb_hotplug_deregister_callback(*s_libusb_context, s_hotplug_handle);
-#endif
-#endif
   Reset();
 
 #if GCADAPTER_USE_LIBUSB_IMPLEMENTATION
@@ -766,6 +767,18 @@ GCPadStatus Input(int chan)
   return pad_state.status;
 }
 
+GCPadStatus PeekInput(int chan)
+{
+  std::lock_guard lk(s_read_mutex);
+  return s_port_states[chan].status;
+}
+
+GCPadStatus GetOrigin(int chan)
+{
+  std::lock_guard lk(s_read_mutex);
+  return s_port_states[chan].origin;
+}
+
 // Get ControllerType from first byte in input payload.
 static ControllerType IdentifyControllerType(u8 data)
 {
diff --git a/Source/Core/InputCommon/GCAdapter.h b/Source/Core/InputCommon/GCAdapter.h
index e6f62e035b..6ce1044d0f 100644
--- a/Source/Core/InputCommon/GCAdapter.h
+++ b/Source/Core/InputCommon/GCAdapter.h
@@ -22,6 +22,11 @@ void StopScanThread();
 // Netplay and CSIDevice_GCAdapter make use of this.
 GCPadStatus Input(int chan);
 
+// Retreive the latest input without changing the new connection flag.
+GCPadStatus PeekInput(int chan);
+
+GCPadStatus GetOrigin(int chan);
+
 void Output(int chan, u8 rumble_command);
 bool IsDetected(const char** error_message);
 bool DeviceConnected(int chan);