diff --git a/tools/packaging/kata-deploy/helm-chart/kata-deploy/templates/custom-runtimes.yaml b/tools/packaging/kata-deploy/helm-chart/kata-deploy/templates/custom-runtimes.yaml
index a8f1338734..6ac3d09aaa 100644
--- a/tools/packaging/kata-deploy/helm-chart/kata-deploy/templates/custom-runtimes.yaml
+++ b/tools/packaging/kata-deploy/helm-chart/kata-deploy/templates/custom-runtimes.yaml
@@ -49,9 +49,20 @@ data:
 {{- end }}
 ---
 # RuntimeClasses for custom runtimes
+{{- $runtimeClassConfigs := fromYaml (include "kata-deploy.runtimeClassConfigs" .) | default dict }}
 {{- range $name, $runtime := .Values.customRuntimes.runtimes }}
 {{- if $runtime.runtimeClass }}
-{{ $runtime.runtimeClass }}
+{{- $runtimeClassObj := fromYaml $runtime.runtimeClass | default dict }}
+{{- $inheritBaseOverhead := true }}
+{{- if hasKey $runtime "inheritBaseOverhead" }}
+{{- $inheritBaseOverhead = $runtime.inheritBaseOverhead }}
+{{- end }}
+{{- if and $inheritBaseOverhead (hasKey $runtimeClassConfigs (default "" $runtime.baseConfig)) }}
+{{- $defaultOverhead := deepCopy (index $runtimeClassConfigs $runtime.baseConfig) }}
+{{- $runtimeOverhead := dig "overhead" "podFixed" (dict) $runtimeClassObj }}
+{{- $_ := set $runtimeClassObj "overhead" (dict "podFixed" (mergeOverwrite $defaultOverhead $runtimeOverhead)) }}
+{{- end }}
+{{ toYaml $runtimeClassObj }}
 ---
 {{- end }}
 {{- end }}
diff --git a/tools/packaging/kata-deploy/helm-chart/kata-deploy/templates/runtimeclasses.yaml b/tools/packaging/kata-deploy/helm-chart/kata-deploy/templates/runtimeclasses.yaml
index 46c3b989f4..0a47eea7b4 100644
--- a/tools/packaging/kata-deploy/helm-chart/kata-deploy/templates/runtimeclasses.yaml
+++ b/tools/packaging/kata-deploy/helm-chart/kata-deploy/templates/runtimeclasses.yaml
@@ -1,3 +1,36 @@
+{{- /*
+  Common RuntimeClass overhead defaults keyed by shim/baseConfig.
+*/ -}}
+{{- define "kata-deploy.runtimeClassConfigs" -}}
+{{- toYaml (dict
+  "clh" (dict "memory" "130Mi" "cpu" "250m")
+  "clh-azure" (dict "memory" "130Mi" "cpu" "250m")
+  "clh-runtime-rs" (dict "memory" "130Mi" "cpu" "250m")
+  "clh-azure-runtime-rs" (dict "memory" "130Mi" "cpu" "250m")
+  "dragonball" (dict "memory" "130Mi" "cpu" "250m")
+  "fc" (dict "memory" "130Mi" "cpu" "250m")
+  "qemu" (dict "memory" "160Mi" "cpu" "250m")
+  "qemu-coco-dev" (dict "memory" "160Mi" "cpu" "250m")
+  "qemu-coco-dev-runtime-rs" (dict "memory" "160Mi" "cpu" "250m")
+  "qemu-runtime-rs" (dict "memory" "160Mi" "cpu" "250m")
+  "qemu-se-runtime-rs" (dict "memory" "1024Mi" "cpu" "1.0")
+  "qemu-se" (dict "memory" "1024Mi" "cpu" "1.0")
+  "qemu-snp" (dict "memory" "2048Mi" "cpu" "1.0")
+  "qemu-snp-runtime-rs" (dict "memory" "2048Mi" "cpu" "1.0")
+  "qemu-tdx" (dict "memory" "2048Mi" "cpu" "1.0")
+  "qemu-tdx-runtime-rs" (dict "memory" "2048Mi" "cpu" "1.0")
+  "qemu-nvidia-gpu" (dict "memory" "10240Mi" "cpu" "1.0")
+  "qemu-nvidia-gpu-runtime-rs" (dict "memory" "10240Mi" "cpu" "1.0")
+  "qemu-nvidia-gpu-snp" (dict "memory" "10240Mi" "cpu" "1.0")
+  "qemu-nvidia-gpu-snp-runtime-rs" (dict "memory" "10240Mi" "cpu" "1.0")
+  "qemu-nvidia-gpu-tdx" (dict "memory" "10240Mi" "cpu" "1.0")
+  "qemu-nvidia-gpu-tdx-runtime-rs" (dict "memory" "10240Mi" "cpu" "1.0")
+  "qemu-cca" (dict "memory" "2048Mi" "cpu" "1.0")
+  "stratovirt" (dict "memory" "130Mi" "cpu" "250m")
+  "remote" (dict "memory" "120Mi" "cpu" "250m")
+) -}}
+{{- end -}}
+
 {{- /*
   Render a single RuntimeClass. Params (dict): root (.), shim, config, shimConfig,
   nameOverride (optional; if set, use as metadata.name for default RC), useShimNodeSelectors.
@@ -95,33 +128,7 @@ scheduling:
 {{- end -}}
 {{- end -}}
 
-{{- $runtimeClassConfigs := dict
-  "clh" (dict "memory" "130Mi" "cpu" "250m")
-  "clh-azure" (dict "memory" "130Mi" "cpu" "250m")
-  "clh-runtime-rs" (dict "memory" "130Mi" "cpu" "250m")
-  "clh-azure-runtime-rs" (dict "memory" "130Mi" "cpu" "250m")
-  "dragonball" (dict "memory" "130Mi" "cpu" "250m")
-  "fc" (dict "memory" "130Mi" "cpu" "250m")
-  "qemu" (dict "memory" "160Mi" "cpu" "250m")
-  "qemu-coco-dev" (dict "memory" "160Mi" "cpu" "250m")
-  "qemu-coco-dev-runtime-rs" (dict "memory" "160Mi" "cpu" "250m")
-  "qemu-runtime-rs" (dict "memory" "160Mi" "cpu" "250m")
-  "qemu-se-runtime-rs" (dict "memory" "1024Mi" "cpu" "1.0")
-  "qemu-se" (dict "memory" "1024Mi" "cpu" "1.0")
-  "qemu-snp" (dict "memory" "2048Mi" "cpu" "1.0")
-  "qemu-snp-runtime-rs" (dict "memory" "2048Mi" "cpu" "1.0")
-  "qemu-tdx" (dict "memory" "2048Mi" "cpu" "1.0")
-  "qemu-tdx-runtime-rs" (dict "memory" "2048Mi" "cpu" "1.0")
-  "qemu-nvidia-gpu" (dict "memory" "10240Mi" "cpu" "1.0")
-  "qemu-nvidia-gpu-runtime-rs" (dict "memory" "10240Mi" "cpu" "1.0")
-  "qemu-nvidia-gpu-snp" (dict "memory" "10240Mi" "cpu" "1.0")
-  "qemu-nvidia-gpu-snp-runtime-rs" (dict "memory" "10240Mi" "cpu" "1.0")
-  "qemu-nvidia-gpu-tdx" (dict "memory" "10240Mi" "cpu" "1.0")
-  "qemu-nvidia-gpu-tdx-runtime-rs" (dict "memory" "10240Mi" "cpu" "1.0")
-  "qemu-cca" (dict "memory" "2048Mi" "cpu" "1.0")
-  "stratovirt" (dict "memory" "130Mi" "cpu" "250m")
-  "remote" (dict "memory" "120Mi" "cpu" "250m")
-}}
+{{- $runtimeClassConfigs := fromYaml (include "kata-deploy.runtimeClassConfigs" .) }}
 
 {{- /* Create RuntimeClass for each enabled shim; when default RC is requested, emit it by reusing the same template with nameOverride */ -}}
 {{- $defaultShim := index .Values.defaultShim "amd64" | default (index .Values.defaultShim "arm64") | default (index .Values.defaultShim "s390x") | default (index .Values.defaultShim "ppc64le") }}
diff --git a/tools/packaging/kata-deploy/helm-chart/kata-deploy/values.yaml b/tools/packaging/kata-deploy/helm-chart/kata-deploy/values.yaml
index be04927607..54ffbc3767 100644
--- a/tools/packaging/kata-deploy/helm-chart/kata-deploy/values.yaml
+++ b/tools/packaging/kata-deploy/helm-chart/kata-deploy/values.yaml
@@ -569,6 +569,8 @@ verification:
 #
 # IMPORTANT: The base config is copied AFTER kata-deploy has applied its modifications
 # (debug, proxy, annotations). Custom runtimes inherit these settings from their base.
+# RuntimeClass overhead defaults are also inherited from baseConfig when not set.
+# Set inheritBaseOverhead: false to disable that inheritance for a custom runtime.
 #
 # Usage with values file (recommended):
 #   Create a custom-runtimes.values.yaml file:
@@ -597,6 +599,7 @@ verification:
 #           scheduling:
 #             nodeSelector:
 #               katacontainers.io/kata-runtime: "true"
+#         inheritBaseOverhead: true        # Optional: set false to remove inherited overhead
 #         # Optional: CRI-specific configuration
 #         containerd:
 #           snapshotter: "nydus"  # Configure containerd snapshotter (nydus, erofs, etc.)
@@ -619,6 +622,7 @@ customRuntimes:
   #     dropIn: ""                      # Optional: TOML overrides for config.d
   #     runtimeClass: |
   #       <full RuntimeClass YAML>
+  #     inheritBaseOverhead: true       # Optional: set false to avoid baseConfig overhead inheritance
   #     containerd:
   #       snapshotter: ""  # Optional: nydus, erofs, or empty for default
   #     crio: