diff --git a/api/openapi-spec/swagger.json b/api/openapi-spec/swagger.json
index 0754abf13f6..6465e23d031 100644
--- a/api/openapi-spec/swagger.json
+++ b/api/openapi-spec/swagger.json
@@ -83654,7 +83654,7 @@
       "type": "string"
      },
      "globalDefault": {
-      "description": "globalDefault specifies whether this PriorityClass should be considered as the default priority for pods that do not have any priority class.",
+      "description": "globalDefault specifies whether this PriorityClass should be considered as the default priority for pods that do not have any priority class. Only one PriorityClass can be marked as `globalDefault`. However, if more than one PriorityClasses exists with their `globalDefault` field set to true, the smallest value of such global default PriorityClasses will be used as the default priority.",
       "type": "boolean"
      },
      "kind": {
diff --git a/api/swagger-spec/scheduling.k8s.io_v1alpha1.json b/api/swagger-spec/scheduling.k8s.io_v1alpha1.json
index d2a6aedc565..f6a1545826a 100644
--- a/api/swagger-spec/scheduling.k8s.io_v1alpha1.json
+++ b/api/swagger-spec/scheduling.k8s.io_v1alpha1.json
@@ -799,7 +799,7 @@
      },
      "globalDefault": {
       "type": "boolean",
-      "description": "globalDefault specifies whether this PriorityClass should be considered as the default priority for pods that do not have any priority class."
+      "description": "globalDefault specifies whether this PriorityClass should be considered as the default priority for pods that do not have any priority class. Only one PriorityClass can be marked as `globalDefault`. However, if more than one PriorityClasses exists with their `globalDefault` field set to true, the smallest value of such global default PriorityClasses will be used as the default priority."
      },
      "description": {
       "type": "string",
diff --git a/docs/api-reference/scheduling.k8s.io/v1alpha1/definitions.html b/docs/api-reference/scheduling.k8s.io/v1alpha1/definitions.html
index 5c480a3ca0f..24e467ad970 100755
--- a/docs/api-reference/scheduling.k8s.io/v1alpha1/definitions.html
+++ b/docs/api-reference/scheduling.k8s.io/v1alpha1/definitions.html
@@ -1341,7 +1341,7 @@ Examples:<br>
 </tr>
 <tr>
 <td class="tableblock halign-left valign-top"><p class="tableblock">globalDefault</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">globalDefault specifies whether this PriorityClass should be considered as the default priority for pods that do not have any priority class.</p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">globalDefault specifies whether this PriorityClass should be considered as the default priority for pods that do not have any priority class. Only one PriorityClass can be marked as <code>globalDefault</code>. However, if more than one PriorityClasses exists with their <code>globalDefault</code> field set to true, the smallest value of such global default PriorityClasses will be used as the default priority.</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">false</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">boolean</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">false</p></td>
diff --git a/staging/src/k8s.io/api/scheduling/v1alpha1/generated.proto b/staging/src/k8s.io/api/scheduling/v1alpha1/generated.proto
index 588ef9718b0..e964a76dd4d 100644
--- a/staging/src/k8s.io/api/scheduling/v1alpha1/generated.proto
+++ b/staging/src/k8s.io/api/scheduling/v1alpha1/generated.proto
@@ -43,6 +43,9 @@ message PriorityClass {
 
   // globalDefault specifies whether this PriorityClass should be considered as
   // the default priority for pods that do not have any priority class.
+  // Only one PriorityClass can be marked as `globalDefault`. However, if more than
+  // one PriorityClasses exists with their `globalDefault` field set to true,
+  // the smallest value of such global default PriorityClasses will be used as the default priority.
   // +optional
   optional bool globalDefault = 3;
 
diff --git a/staging/src/k8s.io/api/scheduling/v1alpha1/types_swagger_doc_generated.go b/staging/src/k8s.io/api/scheduling/v1alpha1/types_swagger_doc_generated.go
index 4b68bf04a47..9080dd9d68c 100644
--- a/staging/src/k8s.io/api/scheduling/v1alpha1/types_swagger_doc_generated.go
+++ b/staging/src/k8s.io/api/scheduling/v1alpha1/types_swagger_doc_generated.go
@@ -31,7 +31,7 @@ var map_PriorityClass = map[string]string{
 	"":              "PriorityClass defines mapping from a priority class name to the priority integer value. The value can be any valid integer.",
 	"metadata":      "Standard object's metadata. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata",
 	"value":         "The value of this priority class. This is the actual priority that pods receive when they have the name of this class in their pod spec.",
-	"globalDefault": "globalDefault specifies whether this PriorityClass should be considered as the default priority for pods that do not have any priority class.",
+	"globalDefault": "globalDefault specifies whether this PriorityClass should be considered as the default priority for pods that do not have any priority class. Only one PriorityClass can be marked as `globalDefault`. However, if more than one PriorityClasses exists with their `globalDefault` field set to true, the smallest value of such global default PriorityClasses will be used as the default priority.",
 	"description":   "description is an arbitrary string that usually provides guidelines on when this priority class should be used.",
 }