Mark Harmon was 21 in Sonic Boom when he played the character 'Student Controller'.
That was over 50 years ago in 1974.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 72, and has starred in 45 movies in total, 43 of those since Sonic Boom was released.
In Sonic Boom, I think Mark Harmon looks: