Best known as the star and co-creator of the FX series Rescue Me, he has also played prominent roles in such films as The Amazing Spider-Man, Draft Day, Operation Dumbo Drop and The Thomas Crown Affair. In 2015, he began starring in the FX series Sex&Drugs&Rock&Roll.
He helped create the Emerson Comedy Workshop while a student at Emerson College in Boston. After graduating, he took a job at the school teaching comedy writing classes.
He voiced the saber-toothed cat Diego in the Ice Age films.
He married Ann Lembeck Leary in 1989, and they had a son named Jack in 1990 and a daughter named Devin in 1992.
He played a supporting role in the 1999 Clint Eastwood film True Crime.