LeFevour completed 21 of 30 passes for 361 yards, including a 53-yard touchdown pass to Brandon Banks on Hamilton's first possession of Saturday's game. He also rushed for 109 yards and a touchdown.
LeFevour was starting in place of Zach Collaros, who is on the six-game injured list with head and back injuries.
Saskatchewan teammates John Chick and Sam Hurl were awarded the top defensive and top Canadian honours respectively.
Chick, a defensive end, sacked Argonauts quarterback Ricky Ray twice, forced a fumble and added a tackle in the Roughriders' 37-9 win over Toronto at Mosaic Stadium on Saturday.
Linebacker Hurl, a Calgary native, had seven tackles and recovered a fumble.
Winnipeg kicker/punter Lirim Hajrullahu won the special teams award. The rookie from St. Catharines, Ont., connected on all five field-goal attempts and scored 17 points in the Blue Bombers' 23-6 road win over the B.C. Lions on Friday.