diff --git a/src/modules/Elsa.Workflows.Core/Abstractions/Activity.cs b/src/modules/Elsa.Workflows.Core/Abstractions/Activity.cs
index 0ef11e6d8..1548daa0c 100644
--- a/src/modules/Elsa.Workflows.Core/Abstractions/Activity.cs
+++ b/src/modules/Elsa.Workflows.Core/Abstractions/Activity.cs
@@ -68,7 +68,7 @@ public abstract class Activity : IActivity, ISignalHandler
     /// will execute synchronously, while activities of the <see cref="ActivityKind.Job"/> kind will execute asynchronously.
     /// </summary>
     [JsonIgnore]
-    public bool RunAsynchronously
+    public bool? RunAsynchronously
     {
         get => this.GetRunAsynchronously();
         set => this.SetRunAsynchronously(value);
diff --git a/src/modules/Elsa.Workflows.Core/Activities/Flowchart/Serialization/FlowchartJsonConverter.cs b/src/modules/Elsa.Workflows.Core/Activities/Flowchart/Serialization/FlowchartJsonConverter.cs
index 4e0053ae4..b4658043a 100644
--- a/src/modules/Elsa.Workflows.Core/Activities/Flowchart/Serialization/FlowchartJsonConverter.cs
+++ b/src/modules/Elsa.Workflows.Core/Activities/Flowchart/Serialization/FlowchartJsonConverter.cs
@@ -1,4 +1,4 @@
-using System.Text.Json;
+using System.Text.Json;
 using System.Text.Json.Serialization;
 using Elsa.Expressions.Contracts;
 using Elsa.Extensions;
@@ -28,6 +28,7 @@ public class FlowchartJsonConverter(IIdentityGenerator identityGenerator, IWellK
         var name = doc.RootElement.TryGetProperty("name", out var nameElement) ? nameElement.GetString() : null;
         var type = doc.RootElement.TryGetProperty("type", out var typeElement) ? typeElement.GetString() : null;
         var version = doc.RootElement.TryGetProperty("version", out var versionElement) ? versionElement.GetInt32() : 1;
+        var runAsynchronously = doc.RootElement.TryGetProperty("runAsynchronously", out var runAsyncElement) && runAsyncElement.GetBoolean();
 
         var connectionsElement = doc.RootElement.TryGetProperty("connections", out var connectionsEl) ? connectionsEl : default;
         var activitiesElement = doc.RootElement.TryGetProperty("activities", out var activitiesEl) ? activitiesEl : default;
@@ -60,6 +61,7 @@ public class FlowchartJsonConverter(IIdentityGenerator identityGenerator, IWellK
             NodeId = nodeId!,
             Name = name,
             Type = type!,
+            RunAsynchronously = runAsynchronously,
             Version = version,
             CustomProperties = customProperties,
             Metadata = metadata,
diff --git a/src/modules/Elsa.Workflows.Core/Attributes/TaskActivityAttribute.cs b/src/modules/Elsa.Workflows.Core/Attributes/TaskActivityAttribute.cs
new file mode 100644
index 000000000..390cfd628
--- /dev/null
+++ b/src/modules/Elsa.Workflows.Core/Attributes/TaskActivityAttribute.cs
@@ -0,0 +1,19 @@
+namespace Elsa.Workflows.Attributes;
+
+[AttributeUsage(AttributeTargets.Class)]
+public class TaskActivityAttribute : ActivityAttribute
+{
+    public TaskActivityAttribute()
+    {
+        Kind = ActivityKind.Task;
+    }
+    
+    public TaskActivityAttribute(string @namespace, string? category, string? description = null, bool runAsynchronously = false) 
+        : base(@namespace, category, description)
+    {
+        Kind = ActivityKind.Task;
+        RunAsynchronously = runAsynchronously;
+    }
+    
+    public bool RunAsynchronously { get; set; }
+}
\ No newline at end of file
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/ActivityPropertyExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/ActivityPropertyExtensions.cs
index ff9bee7c5..938134cc1 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/ActivityPropertyExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/ActivityPropertyExtensions.cs
@@ -29,14 +29,17 @@ public static class ActivityPropertyExtensions
     /// By default, activities with an <see cref="ActivityKind"/> of <see cref="Action"/>, <see cref="Task"/> or <see cref="Trigger"/>
     /// will execute synchronously, while activities of the <see cref="ActivityKind.Job"/> kind will execute asynchronously.
     /// </summary>
-    public static bool GetRunAsynchronously(this IActivity activity) => activity.CustomProperties.GetValueOrDefault(RunAsynchronouslyPropertyName, () => false);
+    public static bool? GetRunAsynchronously(this IActivity activity)
+    {
+        return activity.CustomProperties.GetValueOrDefault<bool?>(RunAsynchronouslyPropertyName, defaultValueFactory: () => null);
+    }
 
     /// <summary>
     /// Sets a flag indicating if this activity should execute synchronously or asynchronously.
     /// By default, activities with an <see cref="ActivityKind"/> of <see cref="Action"/>, <see cref="Task"/> or <see cref="Trigger"/>
     /// will execute synchronously, while activities of the <see cref="ActivityKind.Job"/> kind will execute asynchronously.
     /// </summary>
-    public static void SetRunAsynchronously(this IActivity activity, bool value) => activity.CustomProperties[RunAsynchronouslyPropertyName[0]] = value;
+    public static void SetRunAsynchronously(this IActivity activity, bool? value) => activity.CustomProperties[RunAsynchronouslyPropertyName[0]] = value ?? false;
 
     /// <summary>
     /// Gets the source file and line number where this activity was instantiated, if any.
diff --git a/src/modules/Elsa.Workflows.Core/Services/ActivityFactory.cs b/src/modules/Elsa.Workflows.Core/Services/ActivityFactory.cs
index 081550a0d..4dbed1dc3 100644
--- a/src/modules/Elsa.Workflows.Core/Services/ActivityFactory.cs
+++ b/src/modules/Elsa.Workflows.Core/Services/ActivityFactory.cs
@@ -2,6 +2,7 @@
 using System.Text.Json.Nodes;
 using Elsa.Expressions.Helpers;
 using Elsa.Extensions;
+using Elsa.Workflows.Attributes;
 using Elsa.Workflows.Memory;
 using Elsa.Workflows.Models;
 using Humanizer;
@@ -34,7 +35,18 @@ public class ActivityFactory : IActivityFactory
 
         // 7) Pull out your boolean flags from the cleaned element
         var canStartWorkflow = GetBoolean(cleanedElement, "canStartWorkflow");
-        var runAsynchronously = GetBoolean(cleanedElement, "runAsynchronously");
+        var runAsynchronously = GetNullableBoolean(cleanedElement, "runAsynchronously");
+        if (runAsynchronously is null)
+        {
+            if (context.ActivityDescriptor.Attributes.OfType<TaskActivityAttribute>().FirstOrDefault() is { } taskActivityAttribute)
+            {
+                runAsynchronously = taskActivityAttribute.RunAsynchronously;
+            }
+            else
+            {
+                runAsynchronously = false;
+            }
+        }
 
         // 8) If composite, setup
         if (activity is IComposite composite)
@@ -180,6 +192,11 @@ public class ActivityFactory : IActivityFactory
     }
 
     private static bool GetBoolean(JsonElement element, string propertyName)
+    {
+        return GetNullableBoolean(element, propertyName) ?? false; 
+    }
+    
+    private static bool? GetNullableBoolean(JsonElement element, string propertyName)
     {
         var propertyNames = new[] { propertyName.Camelize(), propertyName.Pascalize() };
 
@@ -188,13 +205,14 @@ public class ActivityFactory : IActivityFactory
             if (element.TryGetProperty("customProperties", out var customPropertyElement))
             {
                 if (customPropertyElement.TryGetProperty(name, out var canStartWorkflowElement))
-                    return canStartWorkflowElement.GetBoolean();
+                    return (bool?)canStartWorkflowElement.GetValue();
             }
 
-            if (element.TryGetProperty(propertyName.Camelize(), out var property) && property.GetBoolean())
-                return true;
+            if (element.TryGetProperty(propertyName.Camelize(), out var property) 
+                && (bool?)property.GetValue() is { } propValue)
+                return propValue;
         }
 
-        return false;
+        return null;
     }
 }
diff --git a/src/modules/Elsa.Workflows.Runtime/Middleware/Activities/BackgroundActivityInvokerMiddleware.cs b/src/modules/Elsa.Workflows.Runtime/Middleware/Activities/BackgroundActivityInvokerMiddleware.cs
index e744870a3..30277beb9 100644
--- a/src/modules/Elsa.Workflows.Runtime/Middleware/Activities/BackgroundActivityInvokerMiddleware.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Middleware/Activities/BackgroundActivityInvokerMiddleware.cs
@@ -1,6 +1,7 @@
 using System.Text.Json;
 using Elsa.Extensions;
 using Elsa.Mediator.Contracts;
+using Elsa.Workflows.Attributes;
 using Elsa.Workflows.CommitStates;
 using Elsa.Workflows.Middleware.Activities;
 using Elsa.Workflows.Models;
@@ -103,7 +104,28 @@ public class BackgroundActivityInvokerMiddleware(
 
         return !GetIsBackgroundExecution(context)
                && context.WorkflowExecutionContext.ExecuteDelegate == null
-               && (kind is ActivityKind.Job || (kind == ActivityKind.Task && activity.GetRunAsynchronously()));
+               && (kind is ActivityKind.Job || GetTaskRunAsynchronously(context));
+    }
+
+    private static bool GetTaskRunAsynchronously(ActivityExecutionContext context)
+    {
+        var activity = context.Activity;
+        var activityDescriptor = context.ActivityDescriptor;
+        var kind = activityDescriptor.Kind;
+
+        if (kind is not ActivityKind.Task)
+            return false;
+        
+        var runAsynchronously = activity.GetRunAsynchronously();
+
+        if (runAsynchronously is null)
+        {
+            var taskActivityAttribute = activityDescriptor.Attributes.OfType<TaskActivityAttribute>().FirstOrDefault();
+            
+            return taskActivityAttribute is { RunAsynchronously: true };
+        }
+
+        return (bool)runAsynchronously;
     }
 
     private static bool GetIsBackgroundExecution(ActivityExecutionContext context) => context.TransientProperties.ContainsKey(BackgroundActivityExecutionContextExtensions.IsBackgroundExecution);
diff --git a/test/integration/Elsa.Workflows.IntegrationTests/Scenarios/RunAsynchronousActivityOutput/Tests.cs b/test/integration/Elsa.Workflows.IntegrationTests/Scenarios/RunAsynchronousActivityOutput/Tests.cs
index ffe94bfab..a5b37596c 100644
--- a/test/integration/Elsa.Workflows.IntegrationTests/Scenarios/RunAsynchronousActivityOutput/Tests.cs
+++ b/test/integration/Elsa.Workflows.IntegrationTests/Scenarios/RunAsynchronousActivityOutput/Tests.cs
@@ -14,7 +14,7 @@ public class Tests
     [Theory(DisplayName = "Activity outputs captured in activity execution record")]
     [InlineData(true)]
     [InlineData(false)]
-    public async Task ActivityOutputCaptureTest(bool runAsynchronously)
+    public async Task ActivityOutputCaptureTest(bool? runAsynchronously)
     {
         // Arrange
         var workflow = new TestWorkflow(workflowBuilder =>
@@ -76,7 +76,7 @@ public class Tests
     [Theory(DisplayName = "Activity outputs captured in activity execution record")]
     [InlineData(true)]
     [InlineData(false)]
-    public async Task ActivityOutputCaptureParallelTest(bool runAsynchronously)
+    public async Task ActivityOutputCaptureParallelTest(bool? runAsynchronously)
     {
         // Arrange
         var workflow = new TestWorkflow(workflowBuilder =>
diff --git a/test/integration/Elsa.Workflows.IntegrationTests/Serialization/ContainerSerialization/Tests.cs b/test/integration/Elsa.Workflows.IntegrationTests/Serialization/ContainerSerialization/Tests.cs
index ed02ac470..e3f2c9716 100644
--- a/test/integration/Elsa.Workflows.IntegrationTests/Serialization/ContainerSerialization/Tests.cs
+++ b/test/integration/Elsa.Workflows.IntegrationTests/Serialization/ContainerSerialization/Tests.cs
@@ -32,17 +32,23 @@ public class Tests
         {
             Id = "start",
             Name = "Start",
+            RunAsynchronously = false // Manually set to false because the manual construction defaults to null,
+                                      // But deserialization uses the factory creation method that overwrites null values.
         };
         var writeLine = new WriteLine(new Input<string>(new Expression("JavaScript", "getVariable('TextVar')")))
         {
             Id = "writeLine",
             Name = "WriteLine",
             Version = 3,
+            RunAsynchronously = false // Manually set to false because the manual construction defaults to null,
+                                      // But deserialization uses the factory creation method that overwrites null values.
         };
         var end = new End
         {
             Id = "end",
             Name = "end",
+            RunAsynchronously = false // Manually set to false because the manual construction defaults to null,
+                                      // But deserialization uses the factory creation method that overwrites null values.
         };
         var container = new Flowchart
         {
@@ -74,6 +80,7 @@ public class Tests
                 new(writeLine, end),
             },
         };
+        container.RunAsynchronously = false;
 
         // Act
 
@@ -107,6 +114,8 @@ public class Tests
                     Id = "writeLine",
                     Name = "WriteLine",
                     CanStartWorkflow = true,
+                    RunAsynchronously = false // Manually set to false because the manual construction defaults to null,
+                                              // But deserialization uses the factory creation method that overwrites null values.
                 },
             },
             CustomProperties = new Dictionary<string, object>
@@ -120,6 +129,7 @@ public class Tests
                 { "string", "str"},
             }
         };
+        container.RunAsynchronously = false;
 
         // Act
 
@@ -153,6 +163,9 @@ public class Tests
                     Id = "writeLine",
                     Name = "WriteLine",
                     CanStartWorkflow = true,
+                    RunAsynchronously = false // Manually set to false because the manual construction defaults to null,
+                                              // But deserialization uses the factory creation method that overwrites null values.
+                    
                 },
             },
             CustomProperties = new Dictionary<string, object>
@@ -166,6 +179,7 @@ public class Tests
                 { "string", "str"},
             }
         };
+        container.RunAsynchronously = false;
 
         // Act