diff --git a/src/NSwag.ApiDescription.Client/NSwag.ApiDescription.Client.props b/src/NSwag.ApiDescription.Client/NSwag.ApiDescription.Client.props
index 4f970e795c..271ba89224 100644
--- a/src/NSwag.ApiDescription.Client/NSwag.ApiDescription.Client.props
+++ b/src/NSwag.ApiDescription.Client/NSwag.ApiDescription.Client.props
@@ -66,6 +66,7 @@
       <NSwagDictionaryBaseType>$(NSwagDictionaryBaseType)</NSwagDictionaryBaseType>
       <NSwagClassStyle>$(NSwagClassStyle)</NSwagClassStyle>
       <NSwagJsonLibrary>$(NSwagJsonLibrary)</NSwagJsonLibrary>
+      <NSwagJsonPolymorphicSerializationStyle>$(NSwagJsonPolymorphicSerializationStyle)</NSwagJsonPolymorphicSerializationStyle>
       <NSwagGenerateDefaultValues>$(NSwagGenerateDefaultValues)</NSwagGenerateDefaultValues>
       <NSwagGenerateDataAnnotations>$(NSwagGenerateDataAnnotations)</NSwagGenerateDataAnnotations>
       <NSwagExcludedTypeNames>$(NSwagExcludedTypeNames)</NSwagExcludedTypeNames>
@@ -154,6 +155,7 @@
       <NSwagDictionaryBaseType>$(NSwagDictionaryBaseType)</NSwagDictionaryBaseType>
       <NSwagClassStyle>$(NSwagClassStyle)</NSwagClassStyle>
       <NSwagJsonLibrary>$(NSwagJsonLibrary)</NSwagJsonLibrary>
+      <NSwagJsonPolymorphicSerializationStyle>$(NSwagJsonPolymorphicSerializationStyle)</NSwagJsonPolymorphicSerializationStyle>
       <NSwagGenerateDefaultValues>$(NSwagGenerateDefaultValues)</NSwagGenerateDefaultValues>
       <NSwagGenerateDataAnnotations>$(NSwagGenerateDataAnnotations)</NSwagGenerateDataAnnotations>
       <NSwagExcludedTypeNames>$(NSwagExcludedTypeNames)</NSwagExcludedTypeNames>
diff --git a/src/NSwag.ApiDescription.Client/NSwag.ApiDescription.Client.targets b/src/NSwag.ApiDescription.Client/NSwag.ApiDescription.Client.targets
index 46996343e5..17cfa4e144 100644
--- a/src/NSwag.ApiDescription.Client/NSwag.ApiDescription.Client.targets
+++ b/src/NSwag.ApiDescription.Client/NSwag.ApiDescription.Client.targets
@@ -209,6 +209,9 @@
       <CurrentOpenApiReference>
         <Command Condition="'%(NSwagJsonLibrary)' != ''">%(Command) /jsonLibrary:%(NSwagJsonLibrary)</Command>
       </CurrentOpenApiReference>
+      <CurrentOpenApiReference>
+        <Command Condition="'%(NSwagJsonPolymorphicSerializationStyle)' != ''">%(Command) /jsonPolymorphicSerializationStyle:%(NSwagJsonPolymorphicSerializationStyle)</Command>
+      </CurrentOpenApiReference>
       <CurrentOpenApiReference>
         <Command Condition="'%(NSwagGenerateDefaultValues)' != ''">%(Command) /generateDefaultValues:%(NSwagGenerateDefaultValues)</Command>
       </CurrentOpenApiReference>
diff --git a/src/NSwag.Commands/Commands/CodeGeneration/JsonSchemaToCSharpCommand.cs b/src/NSwag.Commands/Commands/CodeGeneration/JsonSchemaToCSharpCommand.cs
index e506599ee0..f9d3c91c66 100644
--- a/src/NSwag.Commands/Commands/CodeGeneration/JsonSchemaToCSharpCommand.cs
+++ b/src/NSwag.Commands/Commands/CodeGeneration/JsonSchemaToCSharpCommand.cs
@@ -148,6 +148,13 @@ public CSharpJsonLibrary JsonLibrary
             set => Settings.JsonLibrary = value;
         }
 
+        [Argument(Name = "JsonPolymorphicSerializationStyle", IsRequired = false, Description = "The CSharp JSON polymorphic serialization style, 'NJsonSchema' or 'SystemTextJson' (default: 'NJsonSchema', 'SystemTextJson' is experimental).")]
+        public CSharpJsonPolymorphicSerializationStyle JsonPolymorphicSerializationStyle
+        {
+            get => Settings.JsonPolymorphicSerializationStyle;
+            set => Settings.JsonPolymorphicSerializationStyle = value;
+        }
+
         [Argument(Name = "GenerateDefaultValues", IsRequired = false, Description = "Specifies whether to generate default values for properties (may generate CSharp 6 code, default: true).")]
         public bool GenerateDefaultValues
         {
diff --git a/src/NSwag.Commands/Commands/CodeGeneration/OpenApiToCSharpCommandBase.cs b/src/NSwag.Commands/Commands/CodeGeneration/OpenApiToCSharpCommandBase.cs
index 914c5ea011..2beea57d9a 100644
--- a/src/NSwag.Commands/Commands/CodeGeneration/OpenApiToCSharpCommandBase.cs
+++ b/src/NSwag.Commands/Commands/CodeGeneration/OpenApiToCSharpCommandBase.cs
@@ -245,6 +245,13 @@ public CSharpJsonLibrary JsonLibrary
             set => Settings.CSharpGeneratorSettings.JsonLibrary = value;
         }
 
+        [Argument(Name = "JsonPolymorphicSerializationStyle", IsRequired = false, Description = "The CSharp JSON polymorphic serialization style, 'NJsonSchema' or 'SystemTextJson' (default: 'NJsonSchema', 'SystemTextJson' is experimental).")]
+        public CSharpJsonPolymorphicSerializationStyle JsonPolymorphicSerializationStyle
+        {
+            get => Settings.CSharpGeneratorSettings.JsonPolymorphicSerializationStyle;
+            set => Settings.CSharpGeneratorSettings.JsonPolymorphicSerializationStyle = value;
+        }
+
         [Argument(Name = "GenerateDefaultValues", IsRequired = false, Description = "Specifies whether to generate default values for properties (may generate CSharp 6 code, default: true).")]
         public bool GenerateDefaultValues
         {
diff --git a/src/NSwag.Sample.NET80Minimal/nswag.json b/src/NSwag.Sample.NET80Minimal/nswag.json
index 3c1f7acba1..5a7d35f0e0 100644
--- a/src/NSwag.Sample.NET80Minimal/nswag.json
+++ b/src/NSwag.Sample.NET80Minimal/nswag.json
@@ -145,6 +145,7 @@
       "dictionaryBaseType": "System.Collections.Generic.Dictionary",
       "classStyle": "Poco",
       "jsonLibrary": "NewtonsoftJson",
+      "jsonPolymorphicSerializationStyle": "NJsonSchema",
       "generateDefaultValues": true,
       "generateDataAnnotations": true,
       "excludedTypeNames": [],
@@ -206,6 +207,7 @@
       "dictionaryBaseType": "System.Collections.Generic.Dictionary",
       "classStyle": "Poco",
       "jsonLibrary": "NewtonsoftJson",
+      "jsonPolymorphicSerializationStyle": "NJsonSchema",
       "generateDefaultValues": true,
       "generateDataAnnotations": true,
       "excludedTypeNames": [],
diff --git a/src/NSwag.Sample.NET90Minimal/nswag.json b/src/NSwag.Sample.NET90Minimal/nswag.json
index 720f576a37..37a8da353f 100644
--- a/src/NSwag.Sample.NET90Minimal/nswag.json
+++ b/src/NSwag.Sample.NET90Minimal/nswag.json
@@ -145,6 +145,7 @@
       "dictionaryBaseType": "System.Collections.Generic.Dictionary",
       "classStyle": "Poco",
       "jsonLibrary": "NewtonsoftJson",
+      "jsonPolymorphicSerializationStyle": "NJsonSchema",
       "generateDefaultValues": true,
       "generateDataAnnotations": true,
       "excludedTypeNames": [],
@@ -206,6 +207,7 @@
       "dictionaryBaseType": "System.Collections.Generic.Dictionary",
       "classStyle": "Poco",
       "jsonLibrary": "NewtonsoftJson",
+      "jsonPolymorphicSerializationStyle": "NJsonSchema",
       "generateDefaultValues": true,
       "generateDataAnnotations": true,
       "excludedTypeNames": [],
diff --git a/src/NSwagStudio/ViewModels/CodeGenerators/SwaggerToCSharpClientGeneratorViewModel.cs b/src/NSwagStudio/ViewModels/CodeGenerators/SwaggerToCSharpClientGeneratorViewModel.cs
index f8b624aef7..aacdc84612 100644
--- a/src/NSwagStudio/ViewModels/CodeGenerators/SwaggerToCSharpClientGeneratorViewModel.cs
+++ b/src/NSwagStudio/ViewModels/CodeGenerators/SwaggerToCSharpClientGeneratorViewModel.cs
@@ -43,6 +43,11 @@ public OpenApiToCSharpClientCommand Command
             .Select(t => (CSharpJsonLibrary)Enum.Parse(typeof(CSharpJsonLibrary), t))
             .ToArray();
 
+        /// <summary>Gets the list of JSON polymorphic serialization styles. </summary>
+        public CSharpJsonPolymorphicSerializationStyle[] JsonPolymorphicSerializationStyles { get; } = Enum.GetNames(typeof(CSharpJsonPolymorphicSerializationStyle))
+            .Select(t => (CSharpJsonPolymorphicSerializationStyle)Enum.Parse(typeof(CSharpJsonPolymorphicSerializationStyle), t))
+            .ToArray();
+
         /// <summary>Gets new line behaviors. </summary>
         public NewLineBehavior[] NewLineBehaviors { get; } = Enum.GetNames(typeof(NewLineBehavior))
             .Select(t => (NewLineBehavior)Enum.Parse(typeof(NewLineBehavior), t))
diff --git a/src/NSwagStudio/Views/CodeGenerators/Views/CSharpSettingsView.xaml b/src/NSwagStudio/Views/CodeGenerators/Views/CSharpSettingsView.xaml
index e94de89fd5..5c32890957 100644
--- a/src/NSwagStudio/Views/CodeGenerators/Views/CSharpSettingsView.xaml
+++ b/src/NSwagStudio/Views/CodeGenerators/Views/CSharpSettingsView.xaml
@@ -104,7 +104,12 @@
                         <ComboBox SelectedItem="{Binding Command.JsonLibrary, Mode=TwoWay}" 
                                   ToolTip="JsonLibrary"
                                   ItemsSource="{Binding JsonLibraries}" Margin="0,0,0,12" />
-                        
+
+                        <TextBlock Text="JSON Polymorphic Serialization Style ('System.Text.Json' is experimental/incomplete!)" FontWeight="Bold" Margin="0,0,0,6" />
+                        <ComboBox SelectedItem="{Binding Command.JsonPolymorphicSerializationStyles, Mode=TwoWay}" 
+                                  ToolTip="JsonLibrary"
+                                  ItemsSource="{Binding JsonPolymorphicSerializationStyles}" Margin="0,0,0,12" />
+
                         <CheckBox IsChecked="{Binding Command.RequiredPropertiesMustBeDefined, Mode=TwoWay}" ToolTip="RequiredPropertiesMustBeDefined" Margin="0,0,0,12">
                             <TextBlock Text="Required properties must be defined in JSON (sets Required.Always when the property is required)" TextWrapping="Wrap" />
                         </CheckBox>