diff --git a/interceptors/logging/interceptors.go b/interceptors/logging/interceptors.go
index ce932a10f..c073d34a7 100644
--- a/interceptors/logging/interceptors.go
+++ b/interceptors/logging/interceptors.go
@@ -146,8 +146,9 @@ func reportable(logger Logger, opts *options) interceptors.CommonReportableFunc
 			fields = fields.WithUnique(customCommonFields(kind, c, opts.grpcLogFields()))
 		} else {
 			// Field dups from context override the common fields.
-			fields = newCommonFields(kind, c).WithUnique(ExtractFields(ctx))
+			fields = newCommonFields(kind, c)
 		}
+		fields = fields.WithUnique(ExtractFields(ctx))
 
 		if !c.IsClient {
 			if peer, ok := peer.FromContext(ctx); ok {
diff --git a/interceptors/logging/logging.go b/interceptors/logging/logging.go
index 53eb1ce20..5f0ce05f1 100644
--- a/interceptors/logging/logging.go
+++ b/interceptors/logging/logging.go
@@ -41,14 +41,17 @@ func newCommonFields(kind string, c interceptors.CallMeta) Fields {
 func customCommonFields(kind string, c interceptors.CallMeta, customFields []string) Fields {
 	commonFields := newCommonFields(kind, c)
 
+	existing := map[any]any{}
+	i := commonFields.Iterator()
+	for i.Next() {
+		k, v := i.At()
+		existing[k] = v
+	}
+
 	newFields := Fields{}
 	for _, key := range customFields {
-		commonFieldIterator := commonFields.Iterator()
-		for commonFieldIterator.Next() {
-			ck, cv := commonFieldIterator.At()
-			if ck == key {
-				newFields = append(newFields, ck, cv)
-			}
+		if _, ok := existing[key]; ok {
+			newFields = append(newFields, key, existing[key])
 		}
 	}
 	return newFields