That was over 15 years ago in 2006.
Today he is 66, and has starred in 38 movies in total, 8 since Open Season was released.
In Open Season, I think Gary Sinise looks:
Open Season scores 6 out of 10 on The Movie Database.
Gary Sinise's first acting role was as 'Austin' in True West, released in 1984 when he was 28.