diff --git a/pkg/mutation/mutators/assign_mutator.go b/pkg/mutation/mutators/assign_mutator.go
index bf343a8d0b7..faaaf2072e1 100644
--- a/pkg/mutation/mutators/assign_mutator.go
+++ b/pkg/mutation/mutators/assign_mutator.go
@@ -18,6 +18,7 @@ import (
 	"github.com/pkg/errors"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
 	runtimeschema "k8s.io/apimachinery/pkg/runtime/schema"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
@@ -28,9 +29,11 @@ var log = logf.Log.WithName("mutation").WithValues(logging.Process, "mutation")
 // AssignMutator is a mutator object built out of a
 // Assign instance.
 type AssignMutator struct {
-	id     types.ID
-	assign *mutationsv1alpha1.Assign
-	path   parser.Path
+	id          types.ID
+	assign      *mutationsv1alpha1.Assign
+	assignValue interface{}
+
+	path parser.Path
 
 	// bindings are the set of GVKs this Mutator applies to.
 	bindings  []runtimeschema.GroupVersionKind
@@ -98,7 +101,7 @@ func (m *AssignMutator) SchemaBindings() []runtimeschema.GroupVersionKind {
 }
 
 func (m *AssignMutator) Value() (interface{}, error) {
-	return types.UnmarshalValue(m.assign.Spec.Parameters.Assign.Raw)
+	return runtime.DeepCopyJSONValue(m.assignValue), nil
 }
 
 func (m *AssignMutator) HasDiff(mutator types.Mutator) bool {
@@ -131,13 +134,15 @@ func (m *AssignMutator) Path() parser.Path {
 
 func (m *AssignMutator) DeepCopy() types.Mutator {
 	res := &AssignMutator{
-		id:     m.id,
-		assign: m.assign.DeepCopy(),
+		id:          m.id,
+		assign:      m.assign.DeepCopy(),
+		assignValue: runtime.DeepCopyJSONValue(m.assignValue),
 		path: parser.Path{
 			Nodes: make([]parser.Node, len(m.path.Nodes)),
 		},
 		bindings: make([]runtimeschema.GroupVersionKind, len(m.bindings)),
 	}
+
 	copy(res.path.Nodes, m.path.Nodes)
 	copy(res.bindings, m.bindings)
 	res.tester = m.tester.DeepCopy()
@@ -208,12 +213,13 @@ func MutatorForAssign(assign *mutationsv1alpha1.Assign) (*AssignMutator, error)
 	}
 
 	return &AssignMutator{
-		id:        id,
-		assign:    assign.DeepCopy(),
-		bindings:  gvks,
-		path:      path,
-		tester:    tester,
-		valueTest: &valueTests,
+		id:          id,
+		assign:      assign.DeepCopy(),
+		assignValue: value,
+		bindings:    gvks,
+		path:        path,
+		tester:      tester,
+		valueTest:   &valueTests,
 	}, nil
 }
 
diff --git a/pkg/mutation/mutators/assignmeta_mutator.go b/pkg/mutation/mutators/assignmeta_mutator.go
index acc2d773f7e..7e6fb352836 100644
--- a/pkg/mutation/mutators/assignmeta_mutator.go
+++ b/pkg/mutation/mutators/assignmeta_mutator.go
@@ -42,9 +42,12 @@ var (
 // AssignMeta instance.
 type AssignMetadataMutator struct {
 	id             types.ID
-	tester         *tester.Tester
 	assignMetadata *mutationsv1alpha1.AssignMetadata
-	path           parser.Path
+	assignValue    string
+
+	path parser.Path
+
+	tester *tester.Tester
 }
 
 // assignMetadataMutator implements mutator.
@@ -60,6 +63,10 @@ func (m *AssignMetadataMutator) Matches(obj client.Object, ns *corev1.Namespace)
 }
 
 func (m *AssignMetadataMutator) Mutate(obj *unstructured.Unstructured) (bool, error) {
+	// Note: Performance here can be improved by ~3x by writing a specialized
+	// function instead of using a generic function. AssignMetadata only ever
+	// mutates metadata.annotations or metadata.labels, and we spend ~70% of
+	// compute covering cases that aren't valid for this Mutator.
 	return core.Mutate(m, m.tester, nil, obj)
 }
 
@@ -91,24 +98,16 @@ func (m *AssignMetadataMutator) HasDiff(mutator types.Mutator) bool {
 func (m *AssignMetadataMutator) DeepCopy() types.Mutator {
 	res := &AssignMetadataMutator{
 		id:             m.id,
-		tester:         m.tester.DeepCopy(),
 		assignMetadata: m.assignMetadata.DeepCopy(),
+		assignValue:    m.assignValue,
 		path:           m.path.DeepCopy(),
+		tester:         m.tester.DeepCopy(),
 	}
 	return res
 }
 
 func (m *AssignMetadataMutator) Value() (interface{}, error) {
-	value, err := types.UnmarshalValue(m.assignMetadata.Spec.Parameters.Assign.Raw)
-	if err != nil {
-		return nil, err
-	}
-	switch t := value.(type) {
-	case string:
-		return value, nil
-	default:
-		return nil, fmt.Errorf("incorrect value for AssignMetadataMutator. Value must be a string. Value: %s Type: %s", value, t)
-	}
+	return m.assignValue, nil
 }
 
 func (m *AssignMetadataMutator) String() string {
@@ -134,7 +133,8 @@ func MutatorForAssignMetadata(assignMeta *mutationsv1alpha1.AssignMetadata) (*As
 	if !ok {
 		return nil, errors.New("spec.parameters.assign must have a string value field for AssignMetadata " + assignMeta.GetName())
 	}
-	if _, ok := value.(string); !ok {
+	valueString, isString := value.(string)
+	if !isString {
 		return nil, errors.New("spec.parameters.assign.value field must be a string for AssignMetadata " + assignMeta.GetName())
 	}
 
@@ -147,9 +147,10 @@ func MutatorForAssignMetadata(assignMeta *mutationsv1alpha1.AssignMetadata) (*As
 
 	return &AssignMetadataMutator{
 		id:             types.MakeID(assignMeta),
-		tester:         t,
 		assignMetadata: assignMeta.DeepCopy(),
+		assignValue:    valueString,
 		path:           path,
+		tester:         t,
 	}, nil
 }