Mac (short for Machiavelli) is a male blue greyhound. In almost all Clifford episodes, he is friends with Cleo, Clifford, and T-Bone, but in the episode "False Friends", he wasn't their friend. His doghouse is full of prizes and awards. From the outside, his doghouse looks like it is normal sized but from the inside it is big and blue. His human is Jetta Handover. Voiced by Cam Clarke. Mac is not in Clifford's Really Big Movie and does not wear a tag.
Mac likes to compete in dog shows. he has an inflated sense of his own importance. Mac dislikes some of the things Cleo, Clifford, and T-Bone like for example nose the can. He thinks it is too noisy. He would do anything for a tummy-yummy. In the episode "Promises, Promises" when Mac was mad with Jetta for not keeping her promise to take Emily Elizabeth to the coral cave, Jetta tries to make Mac feel better with a tummy-yummy. Mac comes to get the tummy-yummy and smiles. When Mac gets the tummy-yummy he goes back to being mad. Also in the episode "Teacher's Pet" Mac wouldn't do any of the tricks his teacher at dog school told him to do to unless he got a tummy-yummy for it. At the end of the episode his teacher even gave him a "tricks for treats" award.