diff --git a/core/src/main/java/org/apache/iceberg/SchemaParser.java b/core/src/main/java/org/apache/iceberg/SchemaParser.java
index 6e0d2a7e5e..549c64948a 100644
--- a/core/src/main/java/org/apache/iceberg/SchemaParser.java
+++ b/core/src/main/java/org/apache/iceberg/SchemaParser.java
@@ -333,6 +333,10 @@ private static String defaultValueToJsonString(byte[] bytes) {
   }
 
   private static String defaultValueToJsonString(Object value) {
+    if (value == null) {
+      // Json string representation of null object is string "null"
+      return "null";
+    }
     if (isPrimitiveClass(value)) {
       return value.toString();
     }