Leo the Lion is the mascot for the Hollywood film studio Metro-Goldwyn-Mayer and one of its predecessors, Goldwyn Pictures, featured in the studio's production logo.

When Stewie convinces Brian to go spend some time with Dylan in "Brian's a Bad Father", Brian concedes that it wouldn't be the worst idea. A cutaway shows a young Leo trying to convince his animal schoolmates that his dream of appearing inside of a circle could come true, to his classmates derisive laughter. Leo gets the final word when his dream comes true as an adult.

Adult Leo is voiced by Jon Daly.