Patrick was born in Marietta, Georgia, the oldest of five children born to Nadine and Robert Patrick Sr. He is of Irish and Scottish descent. He has two sisters named Cheri and Karen, and two brothers named Lewis and Richard, the latter of whom is best known as the lead singer for the rock band Filter. Patrick spent his early life in Bay Village, Ohio.
He did not start to pursue an acting career until his mid-twenties. During his childhood, he did not like to act; in third grade, he refused to wear a pair of green tights required for Peter Pan. He graduated from Farmington High School in Farmington, Michigan in 1977. He was a track and field and football athlete at Bowling Green State University. He dropped out before graduating when he found an interest in drama and acting. After leaving college, Patrick worked as a house painter and continued as such until a boating accident in 1984 in Lake Erie. He swam for three hours in order to save others still stranded on the accident site, and nearly drowned in doing so. After the accident, he moved to Los Angeles at age 26. His main income during his first years was as a bartender, and he often lived in his car. He was then picked up for various small roles in low-budget films. Looking back, he credited his early appearances in films to his "tough-looking exterior".
- Die Hard 2
- Terminator 2: Judgment Day
- Fire in the Sky
- Spy Kids
- Charlie's Angels: Full Throttle
- The Marine
- The Real Adventures of Jonny Quest
- The Sopranos
- The X-Files
- The Unit
- True Blood
- Sons of Anarchy
- He is one of the two actors to portray twins in the Television Universe, with the other being Demetrius Grosse.