11/16/2007 AT 05:10 PM EST
Jason Wahler learned plenty during his short stay in prison – and has emerged with a new sense of purpose, he tells PEOPLE exclusively.
"Jail was a very humbling experience. It gave me time to reflect and really think about my mistakes," says the reality-TV star, 20, who was released Tuesday after serving 18 days.
He added, "It made me want to really focus on my career. I spent my time reading and studying the script for my upcoming film 10,000 Doors
. I am happy to be home with my family and friends and am thankful to them for getting me through this rough time."
The former Hills
star received a 30-day sentence in Washington state for assault
and for being a minor exhibiting signs of intoxication, stemming from a drunken melee
at a Seattle hotel in April. Officials had said he could be released early for good behavior.
Wahler completed rehab over the summer and became engaged
to college tennis player Katja Decker-Sadowski.