Spencer Treat Clark was 7 in It Was Him or Us when he played the character 'Jesse Pomeroy'.
That was over 28 years ago in 1995.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 36, and has starred in 24 movies in total, 21 of those since It Was Him or Us was released.
In It Was Him or Us, I think Spencer Treat Clark looks: