In 1973, he joined a comedy troupe called the Zoo Factory, whose members consisted of Dan Hennessey, Bruce Gordon, Harriet Cohen and Jerelyn Homer.
On television, Stocker played the voice of Beastly, the villain on the Nelvana version of the Care Bears television series The Care Bears.
He and Zoo Factory alumni Dan Hennessey appeared as Thomson and Thompson on The Adventures of Tintin.
In the film industry, he voiced The Wizard's assistant, Dim, in 1987's The Care Bears Adventure in Wonderland, and he played a character named Sol in 1993's Look Who's Talking Now. He was also the voice director on Beyblade, Medabots, Committed, Pandalian, Sailor Moon and recently Di-Gata Defenders.
Currently, Stocker lives near Toronto in Bowmanville, Ontario on 21 acres (85,000 m²) of rural land with his wife, Tara, and his daughter Bailey. He is also at present a member of Toronto's VoiceWorks.