diff --git a/DependencyInjection/MonologExtension.php b/DependencyInjection/MonologExtension.php
index 3230f44e..10533cad 100644
--- a/DependencyInjection/MonologExtension.php
+++ b/DependencyInjection/MonologExtension.php
@@ -24,6 +24,7 @@
 use Symfony\Bridge\Monolog\Processor\TokenProcessor;
 use Symfony\Bridge\Monolog\Processor\WebProcessor;
 use Symfony\Bundle\FullStack;
+use Symfony\Bundle\MonologBundle\MonologBundle;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\DependencyInjection\Argument\BoundArgument;
 use Symfony\Component\DependencyInjection\ChildDefinition;
@@ -50,42 +51,19 @@ class MonologExtension extends Extension
 
     private function levelToMonologConst($level, ContainerBuilder $container)
     {
-        if (null === $level || is_numeric($level)) {
-            return $level;
-        }
-
-        if (defined('Monolog\Logger::'.strtoupper($level))) {
-            return constant('Monolog\Logger::' . strtoupper($level));
-        }
-
-        if (function_exists('enum_exists') && enum_exists(Level::class)) {
-            $factoryName = 'monolog.level.' . md5($level);
-
-            if (!$container->has($factoryName)) {
-                $container->register($factoryName)
-                    ->setClass(Level::class)
-                    ->setFactory([Level::class, 'fromName'])
+        if (is_string($level) && str_contains($level, '%')) {
+            $serviceId = 'monolog.level.' . md5($level);
+            if (!$container->has($serviceId)) {
+                $container->register($serviceId)
+                    ->setClass('int')
+                    ->setFactory([MonologBundle::class, 'levelToMonologConst'])
                     ->setArguments([$level]);
             }
 
-            return new Reference($factoryName);
-        }
-
-        if ($container->hasParameter($level)) {
-            return $this->levelToMonologConst($container->getParameter($level), $container);
-        }
-
-        try {
-            $logLevel = $container->resolveEnvPlaceholders($level, true);
-        } catch (ParameterNotFoundException $notFoundException) {
-            throw new \InvalidArgumentException(sprintf('Could not match "%s" to a log level.', $level));
-        }
-
-        if ($logLevel !== '' && $logLevel !== $level) {
-            return $this->levelToMonologConst($logLevel, $container);
+            return new Reference($serviceId);
         }
 
-        throw new \InvalidArgumentException(sprintf('Could not match "%s" to a log level.', $level));
+        return MonologBundle::levelToMonologConst($level);
     }
 
     /**
diff --git a/MonologBundle.php b/MonologBundle.php
index 12e0cb67..371430af 100644
--- a/MonologBundle.php
+++ b/MonologBundle.php
@@ -14,6 +14,7 @@
 use Monolog\Formatter\JsonFormatter;
 use Monolog\Formatter\LineFormatter;
 use Monolog\Handler\HandlerInterface;
+use Monolog\Level;
 use Symfony\Bundle\MonologBundle\DependencyInjection\Compiler\AddSwiftMailerTransportPass;
 use Symfony\Component\HttpKernel\Bundle\Bundle;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
@@ -50,4 +51,20 @@ public static function includeStacktraces(HandlerInterface $handler)
             $formatter->includeStacktraces();
         }
     }
+
+    /**
+     * @internal
+     */
+    public static function levelToMonologConst($level)
+    {
+        if (null === $level || is_numeric($level)) {
+            return $level;
+        }
+
+        if (defined('Monolog\Logger::'.strtoupper($level))) {
+            return constant('Monolog\Logger::' . strtoupper($level));
+        }
+
+        throw new \InvalidArgumentException(sprintf('Could not match "%s" to a log level.', $level));
+    }
 }