That was over 35 years ago in 1986.
In 1993 he died aged just 23, starring in 22 films in his career, 16 since Stand by Me was released.
In Stand by Me, I think River Phoenix looks:
Stand by Me scores 7.8 out of 10 on The Movie Database.
River Phoenix's first acting role was as 'Brian Ellsworth' in Backwards: The Riddle of Dyslexia, released in 1984 when he was 13.