April Stewart was born around 1968 to a family of entertainers. Her father, Freddie Stewart, was a singer with the Tommy Dorsey Orchestra. She had started acting at the age of four. She graduated from Truckee high in 1987.
Stewart is best known for providing many of the female voices in south Park such as Mrs. Cartman, Shelley Marsh, Mayor McDaniels, Principal Victoria, and Sharon Marsh.