diff --git a/python/gigl/common/services/vertex_ai.py b/python/gigl/common/services/vertex_ai.py
index 1e7b288e..b3ce330c 100644
--- a/python/gigl/common/services/vertex_ai.py
+++ b/python/gigl/common/services/vertex_ai.py
@@ -85,6 +85,7 @@ def get_pipeline() -> int: # NOTE: `get_pipeline` here is  the Pipeline name
 
 DEFAULT_PIPELINE_TIMEOUT_S: Final[int] = 60 * 60 * 36  # 36 hours
 DEFAULT_CUSTOM_JOB_TIMEOUT_S: Final[int] = 60 * 60 * 24  # 24 hours
+BOOT_DISK_PLACEHOLDER: Final[str] = "DISK_TYPE_UNSPECIFIED"
 
 
 @dataclass
@@ -98,7 +99,7 @@ class VertexAiJobConfig:
     accelerator_type: str = "ACCELERATOR_TYPE_UNSPECIFIED"
     accelerator_count: int = 0
     replica_count: int = 1
-    boot_disk_type: str = "pd-ssd"  # Persistent Disk SSD
+    boot_disk_type: str = BOOT_DISK_PLACEHOLDER  # Persistent Disk SSD
     boot_disk_size_gb: int = 100  # Default disk size in GB
     labels: Optional[dict[str, str]] = None
     timeout_s: Optional[
@@ -107,6 +108,15 @@ class VertexAiJobConfig:
     enable_web_access: bool = True
     scheduling_strategy: Optional[aiplatform.gapic.Scheduling.Strategy] = None
 
+    def __post_init__(self):
+        if self.boot_disk_type is BOOT_DISK_PLACEHOLDER:
+            if self.machine_type.startswith("g4-"):
+                logger.info(f"No boot disk type set, and g4 machine detected, using hyperdisk-balanced")
+                self.boot_disk_type = "hyperdisk-balanced" # g4 machines require use of hyperdisk-balanced
+            else:
+                logger.info(f"No boot disk type set, using pd-ssd")
+                self.boot_disk_type = "pd-ssd"
+
 
 class VertexAIService:
     """
diff --git a/python/tests/unit/common/services/__init__.py b/python/tests/unit/common/services/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/python/tests/unit/common/services/vertex_ai_test.py b/python/tests/unit/common/services/vertex_ai_test.py
new file mode 100644
index 00000000..9e2bf6e3
--- /dev/null
+++ b/python/tests/unit/common/services/vertex_ai_test.py
@@ -0,0 +1,36 @@
+import unittest
+
+from parameterized import param, parameterized
+
+from gigl.common.services.vertex_ai import VertexAiJobConfig
+
+
+class VertexAIServiceTest(unittest.TestCase):
+    @parameterized.expand(
+        [
+            param(
+                "g4 machine ; should default to hyperdisk-balanced",
+                machine_type="g4-standard-8",
+                expected_boot_disk_type="hyperdisk-balanced",
+            ),
+            param(
+                "n1 machine ; should default to pd-ssd",
+                machine_type="n1-standard-4",
+                expected_boot_disk_type="pd-ssd",
+            ),
+        ]
+    )
+    def test_default_boot_disk_for_machine(
+        self, _, machine_type, expected_boot_disk_type
+    ):
+        job_config = VertexAiJobConfig(
+            job_name="job_name",
+            container_uri="container_uri",
+            command=["command"],
+            machine_type=machine_type,
+        )
+        self.assertEqual(job_config.boot_disk_type, expected_boot_disk_type)
+
+
+if __name__ == "__main__":
+    unittest.main()