diff --git a/Directory.Build.targets b/Directory.Build.targets
index 1e1a4d93b26a..4712f2352485 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -138,6 +138,25 @@
     <BuildDependsOn>$(BuildDependsOn);_CopySymbolsToArtifacts</BuildDependsOn>
   </PropertyGroup>
 
+  <!-- Enable runtime async for net11.0+ source projects that ship only in the Shared Framework -->
+  <PropertyGroup Condition="'$(IsAspNetCoreApp)' == 'true' AND
+      '$(IsPackable)' != 'true' AND
+      $([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net11.0')) AND
+      '$(UseRuntimeAsync)' != 'false' AND
+      '$(TargetOS)' != 'browser' AND
+      !$(RuntimeIdentifier.StartsWith('browser-'))">
+    <Features>$(Features);runtime-async=on</Features>
+  </PropertyGroup>
+
+  <!-- Also enable runtime async for compatible test projects -->
+  <PropertyGroup Condition="'$(IsTestProject)' == 'true' AND
+      $([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net11.0')) AND
+      '$(UseRuntimeAsync)' != 'false' AND
+      '$(TargetOS)' != 'browser' AND
+      !$(RuntimeIdentifier.StartsWith('browser-'))">
+    <Features>$(Features);runtime-async=on</Features>
+  </PropertyGroup>
+
   <!-- Properties for Package Validation -->
   <PropertyGroup Condition="'$(ExcludeFromSourceOnlyBuild)' != 'true'">
     <EnablePackageValidation Condition="'$(EnablePackageValidation)' == ''">true</EnablePackageValidation>
diff --git a/src/Mvc/Mvc.Core/src/Microsoft.AspNetCore.Mvc.Core.WarningSuppressions.xml b/src/Mvc/Mvc.Core/src/Microsoft.AspNetCore.Mvc.Core.WarningSuppressions.xml
index e179ca1a04b3..91235bbf293d 100644
--- a/src/Mvc/Mvc.Core/src/Microsoft.AspNetCore.Mvc.Core.WarningSuppressions.xml
+++ b/src/Mvc/Mvc.Core/src/Microsoft.AspNetCore.Mvc.Core.WarningSuppressions.xml
@@ -83,13 +83,13 @@
       <argument>ILLink</argument>
       <argument>IL2026</argument>
       <property name="Scope">member</property>
-      <property name="Target">M:Microsoft.AspNetCore.Mvc.Formatters.SystemTextJsonInputFormatter.&lt;ReadRequestBodyAsync&gt;d__9.MoveNext</property>
+      <property name="Target">M:Microsoft.AspNetCore.Mvc.Formatters.SystemTextJsonInputFormatter.ReadRequestBodyAsync(Microsoft.AspNetCore.Mvc.Formatters.InputFormatterContext,System.Text.Encoding)</property>
     </attribute>
     <attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
       <argument>ILLink</argument>
       <argument>IL2026</argument>
       <property name="Scope">member</property>
-      <property name="Target">M:Microsoft.AspNetCore.Mvc.Formatters.SystemTextJsonOutputFormatter.&lt;WriteResponseBodyAsync&gt;d__5.MoveNext</property>
+      <property name="Target">M:Microsoft.AspNetCore.Mvc.Formatters.SystemTextJsonOutputFormatter.WriteResponseBodyAsync(Microsoft.AspNetCore.Mvc.Formatters.OutputFormatterWriteContext,System.Text.Encoding)</property>
     </attribute>
     <attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
       <argument>ILLink</argument>
@@ -101,7 +101,7 @@
       <argument>ILLink</argument>
       <argument>IL2026</argument>
       <property name="Scope">member</property>
-      <property name="Target">M:Microsoft.AspNetCore.Mvc.Infrastructure.SystemTextJsonResultExecutor.&lt;ExecuteAsync&gt;d__4.MoveNext</property>
+      <property name="Target">M:Microsoft.AspNetCore.Mvc.Infrastructure.SystemTextJsonResultExecutor.ExecuteAsync(Microsoft.AspNetCore.Mvc.ActionContext,Microsoft.AspNetCore.Mvc.JsonResult)</property>
     </attribute>
     <attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
       <argument>ILLink</argument>
@@ -113,13 +113,13 @@
       <argument>ILLink</argument>
       <argument>IL2026</argument>
       <property name="Scope">member</property>
-      <property name="Target">M:Microsoft.AspNetCore.Mvc.ModelBinding.Binders.CollectionModelBinder`1.&lt;BindComplexCollectionFromIndexes&gt;d__22.MoveNext</property>
+      <property name="Target">M:Microsoft.AspNetCore.Mvc.ModelBinding.Binders.CollectionModelBinder`1.BindComplexCollectionFromIndexes(Microsoft.AspNetCore.Mvc.ModelBinding.ModelBindingContext,System.Collections.Generic.IEnumerable{System.String})</property>
     </attribute>
     <attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
       <argument>ILLink</argument>
       <argument>IL2026</argument>
       <property name="Scope">member</property>
-      <property name="Target">M:Microsoft.AspNetCore.Mvc.ModelBinding.Binders.ComplexObjectModelBinder.&lt;BindPropertyAsync&gt;d__15.MoveNext</property>
+      <property name="Target">M:Microsoft.AspNetCore.Mvc.ModelBinding.Binders.ComplexObjectModelBinder.BindPropertyAsync(Microsoft.AspNetCore.Mvc.ModelBinding.ModelBindingContext,Microsoft.AspNetCore.Mvc.ModelBinding.ModelMetadata,Microsoft.AspNetCore.Mvc.ModelBinding.IModelBinder,System.String,System.String)</property>
     </attribute>
     <attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
       <argument>ILLink</argument>
@@ -131,7 +131,7 @@
       <argument>ILLink</argument>
       <argument>IL2026</argument>
       <property name="Scope">member</property>
-      <property name="Target">M:Microsoft.AspNetCore.Mvc.ModelBinding.Binders.ComplexTypeModelBinder.&lt;BindProperty&gt;d__11.MoveNext</property>
+      <property name="Target">M:Microsoft.AspNetCore.Mvc.ModelBinding.Binders.ComplexTypeModelBinder.BindProperty(Microsoft.AspNetCore.Mvc.ModelBinding.ModelBindingContext,Microsoft.AspNetCore.Mvc.ModelBinding.ModelMetadata,System.String,System.String)</property>
     </attribute>
     <attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
       <argument>ILLink</argument>
diff --git a/src/Servers/Kestrel/test/InMemory.FunctionalTests/HttpConnectionManagerTests.cs b/src/Servers/Kestrel/test/InMemory.FunctionalTests/HttpConnectionManagerTests.cs
index 053c7340f3a7..da38bd2c5bd9 100644
--- a/src/Servers/Kestrel/test/InMemory.FunctionalTests/HttpConnectionManagerTests.cs
+++ b/src/Servers/Kestrel/test/InMemory.FunctionalTests/HttpConnectionManagerTests.cs
@@ -21,6 +21,7 @@ public class HttpConnectionManagerTests : LoggedTest
 #if !DEBUG
     [ConditionalFact]
     [NoDebuggerCondition]
+    [QuarantinedTest("https://github.com/dotnet/runtime/issues/126735")]
     public async Task CriticalErrorLoggedIfApplicationDoesntComplete()
     {
         ////////////////////////////////////////////////////////////////////////////////////////
diff --git a/src/SignalR/clients/csharp/Client/test/FunctionalTests/Hubs.cs b/src/SignalR/clients/csharp/Client/test/FunctionalTests/Hubs.cs
index 17d09d87818c..f22b370075cc 100644
--- a/src/SignalR/clients/csharp/Client/test/FunctionalTests/Hubs.cs
+++ b/src/SignalR/clients/csharp/Client/test/FunctionalTests/Hubs.cs
@@ -6,6 +6,7 @@
 using System.Linq;
 using System.Reactive.Linq;
 using System.Threading.Channels;
+using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Authentication.JwtBearer;
 using Microsoft.AspNetCore.Authorization;
@@ -150,11 +151,13 @@ public class DynamicTestHub : DynamicHub
 
     public ChannelReader<string> StreamBroken() => TestHubMethodsImpl.StreamBroken();
 
+    [RuntimeAsyncMethodGeneration(false)]
     public async Task CallEcho(string message)
     {
         await Clients.Client(Context.ConnectionId).Echo(message);
     }
 
+    [RuntimeAsyncMethodGeneration(false)]
     public async Task CallHandlerThatDoesntExist()
     {
         await Clients.Client(Context.ConnectionId).NoClientHandler();
diff --git a/src/SignalR/clients/csharp/Client/test/FunctionalTests/RuntimeAsyncMethodGenerationAttribute.cs b/src/SignalR/clients/csharp/Client/test/FunctionalTests/RuntimeAsyncMethodGenerationAttribute.cs
new file mode 100644
index 000000000000..137d30feae90
--- /dev/null
+++ b/src/SignalR/clients/csharp/Client/test/FunctionalTests/RuntimeAsyncMethodGenerationAttribute.cs
@@ -0,0 +1,11 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Polyfill: RuntimeAsyncMethodGenerationAttribute is not yet public API
+namespace System.Runtime.CompilerServices;
+
+[AttributeUsage(AttributeTargets.Method)]
+internal sealed class RuntimeAsyncMethodGenerationAttribute(bool runtimeAsync) : Attribute
+{
+    public bool RuntimeAsync { get; } = runtimeAsync;
+}