Born in Sunderland, England and raised in Alberta, Canada, Rennie was first struck with the passion to act living in the town of Edmonton. Performing roles at the A.B.O.P. Theatre in Edmonton, and moving on to an uplifting season at the Shaw Festival, Callum was introduced to the art of acting that would prove to be his true destiny.

Relocating to Vancouver, Rennie quickly caught the attention of the casting community and began auditioning for film and television. He appeared in many of the series produced there including Lonesome Dove, The Highlander and The X-Files, and had a co-starring role in the series My Life as a Dog. Rennie's performance as the nerdish boyfriend opposite Sandra Oh in the feature Double Happiness, gained him his reputation as one of Canada's finest actors. In addition to a deluge of critical acclaim, the role earned Rennie his first Genie Award nomination in the Best Supporting Actor category.

Rennie subsequently appeared in many impressive leading roles including the television movie Paris or Somewhere (Canwest Global Network) and the feature film Curtis's Charm. He continued to rivet audiences with his tough-edged performance as Johnny Talent in Bruce McDonald's feature Hard Core Logo, and last year, Rennie received critical praise for his portrayal of con man Jerry Bines in the CBC television adaptation of David Adams Richards' For Those Who Hunt The Wounded Down. His haunting performance as the enigmatic Bines also inspired critics to compare him to American icon James Dean.

In addition to co-starring opposite Paul Gross in Due South this fall, Rennie will also have been seen in the feature films Mastermind (Columbia Pictures), starring Patrick Stewart and Academy Award winner Brenda Fricker; Excess Baggage (Columbia Pictures), with Alicia Silverstone; Tricks (Showtime), with Mimi Rodgers and Tyne Daly; and will co-star in the CBC series Twitch City, scheduled to debut in January 1998.