Born in Musselburgh, Scotland, Munro moved to Toronto at an early age. After graduating from the National Theatre School of Canada in 1967, he quickly established himself as one of the most compelling theatre actors in Canada, performing with Toronto Arts Productions, the National Arts Centre (where he played Hamlet, touring the role nationally), the Citadel Theatre, Theatre Calgary, Tarragon Theatre and the Toronto Free Theatre, as well as at the Shaw Festival and the Stratford Festival