In Brotherhooves Social, he goes to great lengths to win Apple Bloom a blue ribbon at the Sisterhooves Social, and it is stated that the two were considerably close when they were younger.
In the same episode, he is shown to harbor feelings of inferiority and neglect whenever Apple Bloom praises Applejack for her heroics, and becomes envious when Apple Bloom begins spending more time with her for this reason.
The name was spelled "Big Macintosh" on early merchandise packaging, but in mid-2012 the spelling was changed to "Big Mc Intosh", the same spelling used in show production material, on both Deviant Art and Twitter by the show's developer, Lauren Faust, and four times out of five on Twitter by one of the show's writers, M. His name is also spelled "Big Macintosh" in a parody/promo from The Hub in February 2013 and in the IDW comics' My Little Pony: Equestria Girls Holiday Special and My Little Pony: Friends Forever Issue #31.
Little, Brown's My Little Pony Friendship is Magic official guidebook My Little Pony: The Elements of Harmony, the IDW comics' My Little Pony Micro-Series Issue #6, My Little Pony: Friendship is Magic Issue #9, and My Little Pony: Friends Forever Issue #17, and the My Little Pony chapter books Rainbow Dash and the Daring Do Double Dare, Applejack and the Honest-to-Goodness Switcheroo, and Princess Cadance and the Spring Hearts Garden all spell his name "Big Mc Intosh".
By the end of the episode, he learns to "talk less and listen more".