Alex Rocco first started out taking minor acting roles in T.V. shows and movies like Batman and Motor Psycho. In 1972, he starred as Moe Greene in the Oscar-winning movie, The Godfather.
From then on, he starred in crime movies like Detroit 9000 and The Friends of Eddie Coyle. He also had numerous roles in T.V. shows like Mission Impossible, Three for the Road, Starsky and Hutch, and T.J. Hooker. By the late 1980s, he crossed over to comedy in the T.V. show, The Facts of Life. In 1989, he regularly starred in the comedy T.V. show, The Famous Teddy Z, for which he won an Emmy for Best Supporting Actor in a Comedy Series. He continued on to appear in numerous T.V. shows and movies in the following years.
Rocco's career as a voice actor include a few roles in the cartoon shows Family Guy and The Simpsons. He had minor voice-acting roles in the film A Bug's Life and the animated movie Batman: Year One, where he voices Carmine Falcone.
In 2008, he starred in a Super Bowl commercial for the Audi R8, which was a nod to the "dead horse" scene in The Godfather.