diff --git a/package.json b/package.json
index 6669cc7..2218f53 100644
--- a/package.json
+++ b/package.json
@@ -52,6 +52,7 @@
     "theme-check-normalization-smoke": "tsx scripts/theme-check-normalization-smoke.ts",
     "phpunit-diagnostic-artifact-smoke": "tsx scripts/phpunit-diagnostic-artifact-smoke.ts",
     "plugin-check-normalization-smoke": "tsx scripts/plugin-check-normalization-smoke.ts",
+    "bench-bootstrap-files-smoke": "tsx scripts/bench-bootstrap-files-smoke.ts",
     "recipe-bench-smoke": "tsx scripts/recipe-bench-smoke.ts",
     "recipe-browser-bench-metrics-smoke": "tsx scripts/recipe-browser-bench-metrics-smoke.ts",
     "recipe-browser-smoke": "tsx scripts/recipe-browser-smoke.ts",
diff --git a/packages/runtime-core/src/command-registry.ts b/packages/runtime-core/src/command-registry.ts
index ecd726c..8c49caf 100644
--- a/packages/runtime-core/src/command-registry.ts
+++ b/packages/runtime-core/src/command-registry.ts
@@ -74,6 +74,7 @@ export const commandRegistry = [
       { name: "warmup", description: "Warmup iterations before measurement.", format: "non-negative integer" },
       { name: "dependency-slugs", description: "Comma-separated plugin dependency slugs to load.", format: "comma-separated slugs" },
       { name: "env-json", description: "Benchmark environment object.", format: "JSON object" },
+      { name: "bootstrap-files-json", description: "Component-relative bootstrap file fallbacks; the first existing file is loaded before workloads execute.", format: "JSON array" },
       { name: "workloads-json", description: "Explicit workload list.", format: "JSON array" },
     ],
     outputShape: "Benchmark results JSON envelope with component_id, iterations, and scenarios.",
diff --git a/packages/runtime-playground/src/bench-command-handlers.ts b/packages/runtime-playground/src/bench-command-handlers.ts
index bfce4c0..d2a1561 100644
--- a/packages/runtime-playground/src/bench-command-handlers.ts
+++ b/packages/runtime-playground/src/bench-command-handlers.ts
@@ -5,6 +5,7 @@ export interface BenchRunCodeOptions {
   warmupIterations: number
   dependencySlugs: string[]
   env: Record<string, unknown>
+  bootstrapFiles: string[]
   workloads: unknown[]
   wpCliBridge?: { url: string; token: string }
 }
@@ -19,6 +20,7 @@ $iterations = max(1, (int) ${JSON.stringify(String(options.iterations))});
 $warmup_iterations = max(0, (int) ${JSON.stringify(String(options.warmupIterations))});
 $dependency_slugs = json_decode(${JSON.stringify(JSON.stringify(options.dependencySlugs))}, true);
 $bench_env = json_decode(${JSON.stringify(JSON.stringify(options.env))}, true);
+$bootstrap_files = json_decode(${JSON.stringify(JSON.stringify(options.bootstrapFiles))}, true);
 $configured_workloads = json_decode(${JSON.stringify(JSON.stringify(options.workloads))}, true);
 $wp_cli_bridge_url = ${JSON.stringify(options.wpCliBridge?.url ?? null)};
 $wp_cli_bridge_token = ${JSON.stringify(options.wpCliBridge?.token ?? null)};
@@ -155,6 +157,21 @@ foreach ($plugins_to_activate as $plugin_to_activate) {
         throw new RuntimeException($activation->get_error_message());
     }
 }
+$loaded_bootstrap_file = '';
+foreach (is_array($bootstrap_files) ? $bootstrap_files : array() as $bootstrap_file) {
+    if (!is_string($bootstrap_file) || $bootstrap_file === '' || str_contains($bootstrap_file, '..')) {
+        continue;
+    }
+    $bootstrap_path = $plugin_path . '/' . ltrim($bootstrap_file, '/');
+    if (file_exists($bootstrap_path)) {
+        require_once $bootstrap_path;
+        $loaded_bootstrap_file = $bootstrap_file;
+        break;
+    }
+}
+if (is_array($bootstrap_files) && count($bootstrap_files) > 0 && $loaded_bootstrap_file === '') {
+    throw new RuntimeException('No configured wordpress.bench bootstrap files were found.');
+}
 if (!empty($plugins_to_activate)) {
     do_action('plugins_loaded');
     do_action('init');
diff --git a/packages/runtime-playground/src/wordpress-command-runners.ts b/packages/runtime-playground/src/wordpress-command-runners.ts
index 448388f..3d2f166 100644
--- a/packages/runtime-playground/src/wordpress-command-runners.ts
+++ b/packages/runtime-playground/src/wordpress-command-runners.ts
@@ -199,12 +199,13 @@ export async function runBenchCommand({
   const warmupIterations = nonNegativeIntegerArg(args, "warmup", 1)
   const dependencySlugs = commaListArg(args, "dependency-slugs")
   const env = jsonObjectArg(args, "env-json")
+  const bootstrapFiles = jsonArrayArg(args, "bootstrap-files-json").filter((file): file is string => typeof file === "string")
   const workloads = jsonArrayArg(args, "workloads-json")
   const bridge = benchWorkloadsUseWpCli(workloads) ? await createRuntimeWpCliBridge(server) : undefined
   let response: PlaygroundRunResponse
   try {
     response = await runPlaygroundCommand("wordpress.bench", server, {
-      code: bootstrapPhpCode(runtimeSpec, benchRunCode({ componentId, pluginSlug, iterations, warmupIterations, dependencySlugs, env, workloads, wpCliBridge: bridge }), []),
+      code: bootstrapPhpCode(runtimeSpec, benchRunCode({ componentId, pluginSlug, iterations, warmupIterations, dependencySlugs, env, bootstrapFiles, workloads, wpCliBridge: bridge }), []),
     })
     assertPlaygroundResponseOk("wordpress.bench", response)
   } finally {
diff --git a/scripts/bench-bootstrap-files-smoke.ts b/scripts/bench-bootstrap-files-smoke.ts
new file mode 100644
index 0000000..862c74c
--- /dev/null
+++ b/scripts/bench-bootstrap-files-smoke.ts
@@ -0,0 +1,27 @@
+import assert from "node:assert/strict"
+import { benchRunCode } from "../packages/runtime-playground/src/bench-command-handlers.js"
+
+const code = benchRunCode({
+  componentId: "fixture-plugin",
+  pluginSlug: "fixture-plugin",
+  iterations: 1,
+  warmupIterations: 0,
+  dependencySlugs: [],
+  env: {},
+  bootstrapFiles: ["lib/compat/new.php", "lib/compat/old.php"],
+  workloads: [],
+})
+
+assert.match(code, /\$bootstrap_files = json_decode/)
+assert.match(code, /lib\/compat\/new\.php/)
+assert.match(code, /lib\/compat\/old\.php/)
+assert.match(code, /foreach \(is_array\(\$bootstrap_files\)/)
+assert.match(code, /require_once \$bootstrap_path/)
+assert.match(code, /break;/)
+assert.match(code, /do_action\('plugins_loaded'\)/)
+assert.ok(
+  code.indexOf("require_once $bootstrap_path") < code.indexOf("do_action('plugins_loaded')"),
+  "bootstrap files should load before synthetic plugins_loaded/init hooks"
+)
+
+console.log("Bench bootstrap files smoke passed")