Haruo Nakajima, the Japanese actor who played the movie monster Godzilla in a dozen films and whose booming steps in a 200-pound rubber suit sent the denizens of Tokyo running into cinematic history, died on Monday. He was 88.

His daughter, Sonoe Nakajima, said the cause was pneumonia. She did not say where he died.

Mr. Nakajima was a 25-year-old stunt actor with just four movies to his credit when he was cast in what are perhaps Japan’s two most famous films of that era, both released in 1954: Akira Kurosawa’s masterpiece “Seven Samurai,” in which he had a bit part, and “Godzilla.”

In “Godzilla” he played the title character: a gigantic, irradiated lizard whose mutated form and destructive power wreak havoc on Tokyo. The first movie in a long-running franchise, it was released nine years after the bombings of Hiroshima and Nagasaki as a not-so-thinly veiled fable about the dangers of nuclear weapons.