That was over 34 years ago in 1986.
Today he is 65, and has starred in 121 movies in total, 105 since Platoon was released.
In Platoon, I think Willem Dafoe looks:
Platoon scores 7.6 out of 10 on The Movie Database.
Willem Dafoe's first acting role was as 'Willy (uncredited)' in Heaven's Gate, released in 1980 when he was 25.