The six-foot, 217-pound Calgary Stampeders running back received the honour Thursday at the CFL awards banquet.
Montreal Alouettes linebacker Shea Emry was a finalist for the award in voting conducted by the Football Reporters of Canada and the eight CFL head coaches.
Cornish, a native of New Westminster, B.C., is also a finalist for the CFL's outstanding player award with Toronto's Chad Owens.
Cornish led the CFL in rushing with 1,457 yards, becoming the first Canadian to do so since Orville Lee achieved the feat in '88 with Ottawa.
Cornish also broke Norm Kwong's 56-year-old record for most rushing yards in a season by a Canuck of 1,437.
Emry, a native of Richmond, B.C., had a career-best 87 tackles this season with seven sacks with Montreal.
The CFL awards are sponsored by Gibson's Finest.