diff --git a/metadata-ingestion/scripts/avro_codegen.py b/metadata-ingestion/scripts/avro_codegen.py
index 2841985ad0..0fe79a2c6a 100644
--- a/metadata-ingestion/scripts/avro_codegen.py
+++ b/metadata-ingestion/scripts/avro_codegen.py
@@ -346,7 +346,7 @@ def write_urn_classes(key_aspects: List[dict], urn_dir: Path) -> None:
     code = """
 # This file contains classes corresponding to entity URNs.
 
-from typing import ClassVar, List, Optional, Type, TYPE_CHECKING
+from typing import ClassVar, List, Optional, Type, TYPE_CHECKING, Union
 
 import functools
 from deprecated.sphinx import deprecated as _sphinx_deprecated
@@ -547,10 +547,31 @@ def generate_urn_class(entity_type: str, key_aspect: dict) -> str:
         assert fields[0]["type"] == ["null", "string"]
         fields[0]["type"] = "string"
 
+    field_urn_type_classes = {}
+    for field in fields:
+        # Figure out if urn types are valid for each field.
+        field_urn_type_class = None
+        if field_name(field) == "platform":
+            field_urn_type_class = "DataPlatformUrn"
+        elif field.get("Urn"):
+            if len(field.get("entityTypes", [])) == 1:
+                field_entity_type = field["entityTypes"][0]
+                field_urn_type_class = f"{capitalize_entity_name(field_entity_type)}Urn"
+            else:
+                field_urn_type_class = "Urn"
+
+        field_urn_type_classes[field_name(field)] = field_urn_type_class
+
     _init_arg_parts: List[str] = []
     for field in fields:
+        field_urn_type_class = field_urn_type_classes[field_name(field)]
+
         default = '"PROD"' if field_name(field) == "env" else None
-        _arg_part = f"{field_name(field)}: {field_type(field)}"
+
+        type_hint = field_type(field)
+        if field_urn_type_class:
+            type_hint = f'Union["{field_urn_type_class}", str]'
+        _arg_part = f"{field_name(field)}: {type_hint}"
         if default:
             _arg_part += f" = {default}"
         _init_arg_parts.append(_arg_part)
@@ -579,16 +600,7 @@ def generate_urn_class(entity_type: str, key_aspect: dict) -> str:
         init_validation += f'if not {field_name(field)}:\n    raise InvalidUrnError("{class_name} {field_name(field)} cannot be empty")\n'
 
         # Generalized mechanism for validating embedded urns.
-        field_urn_type_class = None
-        if field_name(field) == "platform":
-            field_urn_type_class = "DataPlatformUrn"
-        elif field.get("Urn"):
-            if len(field.get("entityTypes", [])) == 1:
-                field_entity_type = field["entityTypes"][0]
-                field_urn_type_class = f"{capitalize_entity_name(field_entity_type)}Urn"
-            else:
-                field_urn_type_class = "Urn"
-
+        field_urn_type_class = field_urn_type_classes[field_name(field)]
         if field_urn_type_class:
             init_validation += f"{field_name(field)} = str({field_name(field)})\n"
             init_validation += (
@@ -608,7 +620,7 @@ def generate_urn_class(entity_type: str, key_aspect: dict) -> str:
             init_coercion += "    platform_name = DataPlatformUrn.from_string(platform_name).platform_name\n"
 
         if field_name(field) == "platform":
-            init_coercion += "platform = DataPlatformUrn(platform).urn()\n"
+            init_coercion += "platform = platform.urn() if isinstance(platform, DataPlatformUrn) else DataPlatformUrn(platform).urn()\n"
         elif field_urn_type_class is None:
             # For all non-urns, run the value through the UrnEncoder.
             init_coercion += (
diff --git a/metadata-ingestion/tests/unit/urns/test_urn.py b/metadata-ingestion/tests/unit/urns/test_urn.py
index 0c362473c0..bee80ec331 100644
--- a/metadata-ingestion/tests/unit/urns/test_urn.py
+++ b/metadata-ingestion/tests/unit/urns/test_urn.py
@@ -4,7 +4,13 @@ from typing import List
 
 import pytest
 
-from datahub.metadata.urns import CorpUserUrn, DatasetUrn, Urn
+from datahub.metadata.urns import (
+    CorpUserUrn,
+    DataPlatformUrn,
+    DatasetUrn,
+    SchemaFieldUrn,
+    Urn,
+)
 from datahub.utilities.urns.error import InvalidUrnError
 
 pytestmark = pytest.mark.filterwarnings("ignore::DeprecationWarning")
@@ -60,6 +66,20 @@ def test_urn_coercion() -> None:
     assert urn == Urn.from_string(urn.urn())
 
 
+def test_urns_in_init() -> None:
+    platform = DataPlatformUrn("abc")
+    assert platform.urn() == "urn:li:dataPlatform:abc"
+
+    dataset_urn = DatasetUrn(platform, "def", "PROD")
+    assert dataset_urn.urn() == "urn:li:dataset:(urn:li:dataPlatform:abc,def,PROD)"
+
+    schema_field = SchemaFieldUrn(dataset_urn, "foo")
+    assert (
+        schema_field.urn()
+        == "urn:li:schemaField:(urn:li:dataset:(urn:li:dataPlatform:abc,def,PROD),foo)"
+    )
+
+
 def test_urn_type_dispatch_1() -> None:
     urn = Urn.from_string("urn:li:dataset:(urn:li:dataPlatform:abc,def,PROD)")
     assert isinstance(urn, DatasetUrn)