He first began stage acting while attending John Rennie High School, where he met future collaborators Donovan King and Tetsuro Shigematsu.
Electing to pursue health science at John Abbott College and then biology at Concordia University, Kelly continued performing, co-founding the Wahoo Family Theatre Company with Donovan King and with future sketch comedy partner Matthew Legault.
Having completed his Bachelor of Science degree in 1995, Kelly returned to Concordia in 1996 to begin his formal actor training in Theatre Performance, working alongside future singer-songwriters Pierre Gage and Martha Wainwright.
As a second year thesis assignment, Kelly created a play that would eventually become The Anorak, his critically acclaimed[2][3][4] one-man-show about the École Polytechnique massacre and the life and death of Marc Lépine.
[12][13] After seeing his play in 2006, actress Karine Vanasse and Maxime Rémillard of Remstar Productions recruited Kelly to collaborate with director Denis Villeneuve on his film Polytechnique, released in 2009.
[11] For the 20th anniversary of the massacre, Kelly performed for the first time in a French version of the play (translated by Geneviève Charbonneau) at Université de Montréal.
[22] Kelly was executive producer of Montreal Hearts, a comedy-drama web series nominated for an Indie Soap Award (Fan's Choice)[23] and named on Funny or Die for their Best Videos of 2010.