Complex sentence: John James "Jimmy" MacDonald (19 May 1906--1 February 1991) was a Scottish voice actor and the original head of the Disney sound effects department, and the voice of Mickey Mouse from 1946 to 1977.
Split into simpler sentences: John James "Jimmy" MacDonald (19 May 1906--1 February 1991) was a British voice actor and the original head of the Disney sound effects department. He was also the voice of Mickey Mouse from 1946 to 1977.