Kirby was in Hamilton, Ontario to two American expatriates. His mother is from Brooklyn, New York and father grew up "along the eastern seaboard". His parents moved from New York City, New York to Canada in 1974. Kirby studied drama at the National Theatre School of Canada, a theatre conservatory which focuses on classical works.
Luke has appeared in a number of television shows and several movies, including:
Halloween: Resurrection
Lost and Delirious
Mambo Italiano
Luck
Window Teory
Tell Me You Love Me
The Stone Angel
All Hat
Labor Pains
He also did a six-part mini-series called Slings and Arrows.