In 1990, he earned his law degree and was admitted to the Tennessee bar. In 2000, he opened his own law office in Knoxville, Tennessee, where he practiced in the field of criminal defense, juvenile justice, personal injury and sports law. In 2005, he was appointed Judge of the Juvenile Court for Knox County, along with former NFL linebacker Ron McCartney.
Irwin was also a co-founder of the Catholic Youth Football League in Knoxville. The league allows children who do not have a school team to play on a faith-based team and compete together against schools in the area.