Jim was raised by his parents, Joanne and Darcy Watson in North Bay, Ontario, Canada with his two younger brothers, Dean and Nick. Throughout his childhood, Watson played hockey and had dreams of becoming a pro athlete. He attended West Ferris Secondary School, where he had his first leading role in the production of "You're a Good Man, Charlie Brown!" This opportunity lead to his decision to attend George Brown Theatre School to pursue his career as an actor in Toronto.