Has taken over two of Sterling Holloway's characters. He took over the as the voice of Winnie The Pooh after Holloway's death and took over for the voice of Kaa in The Jungle Book 2 (2003).
He had to fill in for Jeremy Irons during the song "Be Prepared" in The Lion King. Jeremy Irons threw out his voice after singing, "You won't get a sniff without me!".
He was also the 1991 alternate of the Shredder for the original "Teenage Mutant Ninja Turtles" (1987/I) series, which is also the same show where he voiced Leatherhead the mutant alligator.
In an interview with Disney comics he cited Darkwing Duck and Don Karnage as two of his favorite roles, stating "they're both probably the closest to me - I kinda improvise a lot of them, kinda ad-lib".
Role as the voice-over actor in Mark Hamill's Comic Book: The Movie (2004) (V) is his only full-bodied, live-action role to date.
The family of the late Louie Prima (who voiced Louie in the original "The Jungle Book" movie) sued Disney because Jim Cummings did too good of a job impersonating Prima when he voiced the character in the TV series spin off, "TaleSpin". As a result, Louie was completely absent from "The Jungle Book 2" and replaced by an Expy named "King Larry" in the TV series "House Of Mouse".