And in the new movie "The Departed," opening this weekend, he plays the landlord of police mole Matt Damon.
Mackenzie also had high praise for Damon.
"He's one of the nicest guys I've ever met," he said. "He really is a mensch. He's so sweet. He was completely supportive."
Matt Damon: more than just a pretty face, chisled body, excellent actor, devoted father and husband and noted philanthropist, apparently.
J.C. Mackenzie grew up in Ottawa and has been supporting himself for 20 years as an actor. And he has a small role in Martin Scorcese's The Departed, which opens today, opposite Matt Damon.
He told me this week that unlike other actors he's worked with over the years, Damon is "a total sweetheart."
"Nicest guy on the planet," he said. "I am not exaggerating - he is the nicest guy on the planet."
Longtime pals Ben Affleck, 34, and Matt Damon, 35, hit it big with their Oscar-winning film Good Will Hunting, but an insider says fame is tearing them apart.
"Matt and Ben just aren't seeing eye to eye lately," the insider tells LifeandStylemag.com. "Ben badly wants to make another film with Matt, and even though it's something they've talked about a lot over the last seven years [since they were co-leads in 1999's Dogma], Matt isn't keen on the idea at all at the moment."
Matt’s publicist denies the rift, saying, "They are genuinely the best of friends," and an insider close to Ben says their relationship is "as strong as ever."
But the insider claims that Matt has also forged a strong friendship with his Ocean's 13 co-star Don Cheadle, and the pair are discussing a number of projects they'd like to collaborate on.
"Matt and Don didn't really get close until they made Ocean's 12 in Europe in 2004 and had a bunch of scenes together," says the insider. "By the time they got around to doing 13, they were old pals and started talking about working more together in the future. They both want to do some low-budget projects next, probably as co-stars."