He performed many character voices for Disney. His distinctive voice can be heard in movies such as Lady and the Tramp, Sleeping Beauty, Donald Duck and His Friends, One Hundred and One Dalmatians, Mary Poppins and Bedknobs and Broomsticks.
He also did voices for several Disney Attractions, such as the famous Big Thunder Mountain Railroad safety spiel, the laughing hyenas in It's a Small World, Ben Franklin in Epcot's The American Adventure, and Zeke in Country Bear Jamboree.
His most well-known later-life role was the Crooked Old Man in Wee Sing: King Cole's Party, which was released in 1987.
- McKennon's Hyena laugh from Lady and the Tramp was then used for the laugh of the famous Crash Bandicoot villain character Ripper Roo, in the Crash Bandicoot video games series.
- The laugh was also use again in various films including the 2003 Christmas comedy film Elf and in the 1979 horror film Tourist Trap.