Marlon Brando was 25 in The Men when he played the character 'Ken Wilcheck/Bud'.
That was over 74 years ago in 1950.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
In 2004 he died aged 80, starring in 97 films in his career, 95 of those after The Men was first released. If he were alive today he would be 100.
In The Men, I think Marlon Brando looks: