Eldest child of the Apple family, Big Mac is a quiet, hard-working stallion, who spends his days bucking apple trees and hauling carts. He usually doesn't say more than the occasional "eyup" and "nope," but when the story focuses on him, he has been known to be quite articulate.
He began to feel insecure and sad that Applejack was the "hero" of the Apple family, as she and the other ponies who represent the Elements of Harmony are always running off to save Equestria, while he's just on the farm doing chores. Desperate to once again be a hero to his youngest sister Apple Bloom, Big Mac disguised himself as a mare, cousin Orchard Blossom, so he could compete in the Sisterhooves Social and help Apple Bloom win a blue ribbon (when Applejack wasn't available). They didn't win, so he felt bad, but Apple Bloom assured him that he will always be a hero to her.
He is a member of the Pony Tones, a singing ensemble. He provides the bass voice.
In season 7, the Cutie Mark Crusaders helped him win the heart of Sugar Belle, a bakery owner. But first, he had to compete with Feather Bangs (a pony who appeared to have been modeled after Justin Bieber), who was always surrounded by three ponies who liked him (who were CLEARLY based on the Bimbettes from Beauty and the Beast).
Hearts and Hooves Day
Where the Apple Lies
Hard To Say Anything
The Perfect Pear
The Break Up Breakdown
Going To Seed
The Big Mac Question
In the series finale of My Little Pony: Friendship is Magic, Big Mac is shown to be married to Sugar Belle, and together they have son, and run Sweet Apple Acres.