Haruo Nakajima, the man who wore the Godzilla suit in the original film, died on Monday aged 88 from pneumonia, Toho studios said in a statement.
Nakajima wore the Godzilla costume, originally made from ready mixed concrete, from 1954 to 1972 for 12 films.
"We would like to express our sincere condolences for the death of Mr. Haruo Nakajima," Toho, which released the Godzilla films, said in a statement.
Nakajima began working as a stuntman shortly after World War II in Tokyo where he was spotted and cast by Ishiro Honda who directed the first Godzilla film in 1954.
The actor told CNN's Great Big Story last year that he studied elephants and gorillas to prepare for his role as Godzilla.
"When the film was a success I was so surprised," Nakajima said. "I was so happy. In the end, the Godzilla I played remains on film forever."