The grandson of actor Pedro Gonzalez-Gonzalez. He has sometimes been credited as Clifton Gonzalez-Gonzalez to honor his grandfather. He first broke through the mainstream in 1997 with a performance as gang thug César Sánchez in the film One Eight Seven. In 1998, he enchanted and amused small screen audiences in Ray Bradbury's cult Latino film The Wonderful Ice Cream Suit.
In 2005, Collins, Jr. won rave reviews for his subtle portrayal of killer Perry Smith in the fact-based film Capote. He starred in the 2005 film Dirty alongside Oscar winner Cuba Gooding, Jr. Collins, Jr. starred on FX Networks' show Thief. Collins, Jr.. He also has a small role in 2006's Babel, directed by Alejandro González Iñárritu.
In 2008, Collins directed two music videos for the country music group, Zac Brown Band: "Chicken Fried" and "Whatever It Is".
Collins starred in the comedy "Sunshine Cleaning" with Amy Adams, Emily Blunt and Alan Arkin.
Collins, Jr. co-produced the film National Lampoon's TV: The Movie in which he plays Officer Sanchez alongside of Jacob Vargas in TJ COPS. He also voiced the fictional video game character Cesar Vialpando in Grand Theft Auto: San Andreas.
Collins might be joining the film Yucatan which is the last screenplay written by Steve McQueen and possibly to be directed by Quentin Tarantino.