Louie the Mountain Lion is an occasional enemy of Donald Duck and Goofy in the theatrical cartoons for which they appear in. His last theatrical appearance was in the Donald Duck short Grand Canyonscope.
Louie is buffoonish and sometimes grumpy. His cartoons often see him chasing after either Donald Duck or Goofy.
He later appears in Goofy's Radio, where he tries to eat Goofy but uncontrollably dances to the music of Goofy's radio.
Louie makes a small appearance in "Goofy's Valentine Date". He also appears in "Pluto Saves the Day" just before "Goofy's Big Kitty" is shown, where Goofy tells him that this cartoon stars Goofy and him, then roars at him making Goofy say him and Goofy.
- His design is identical to the tiger in the Goofy short Tiger Trouble. Drawings of Louie in a model sheet are animation drawings of the tiger from Tiger Trouble but without the stripes. Co-incidentally, Raja the Tiger, the secondary antagonist of the animated short Goliath II, bears a close physical resemblance to both Louie and the tiger from Tiger Trouble.
- His son appears once in Hook, Lion and Sinker. Louie attempts to catch Donald Duck's fishing trip prizes with help of a young lion cub who had to pick bullets out of his backside.
- Grand Canyonscope is the only short that Louie appears in that doesn't have a "lion" pun in the title.