Mac is a bright and somewhat shy 8-year-old boy who visits Foster's. He almost always seems to know what to do when there is a problem. Mac becomes extremely hyperactive to the point of a rabid mania if he eats sugar; once in this state, he will often become obsessed with seeking any other source (and will also sometimes run around naked letting things hang out or in his underwear). Mac also has a hateful rivalry with Frankie Foster. He is voiced by Sean Marqeutte.

Allies: Terrence Enemies: Bloo, Coco, Wilt, Eduardo, Frankie Foster, Duchess Likes: being spanked by Frankie, being in jail, being in time-out, doing mean things to Frankie Dislikes: being kissed by Frankie, helping Frankie, Doing nice things for Frankie Fate: Gets sent to jail by Frankie never to see each other again for the rest of their lives