Andre Durie added a touchdown in the second half for the Argonauts, who built a 24-6 halftime lead and never trailed while playing in front of a loud home crowd of 53,208 at Rogers Centre. Toronto earned its 16th Grey Cup title and first since 2004.
Backup quarterback Jarious Jackson, a former Tupelo standout, completed a one-yard pass to Dontrelle Inman for a Toronto touchdown.
"It feels great. This is what you play for — to be able to be on a team that gets on a run and wins a championship," said Ricky Ray, who threw for 231 yards and two touchdowns. "It just makes you feel so good. It makes you feel like all the hard work and the obstacles that you've overcome just pay off.
"Everybody on this team, you ask them, somewhere they had to overcome something to get to this point. We're a family, we just came together, stuck together and just played great football."
Rene Paredes kicked four field goals for Calgary. Backup Bo Levi Mitchell threw a touchdown pass to Maurice Price in the fourth quarter, and the pair connected again for a 2-point conversion. But it was too late to make a difference.
Chad Kackert had 133 yards rushing for Toronto and was awarded outstanding player of the Grey Cup. Argonauts defensive end Ricky Foley was the most outstanding Canadian in the CFL's marquee game.
Kackert helped compensate for a relatively quiet game from Owens, who was the CFL's outstanding player this season.
"Maybe they keyed on him and we have a lot of great receivers too," Kackert said. "You can't key on anybody."
The Argonauts got off to a fast start behind Owens, who had a 5-yard touchdown reception in the first quarter. The score came after Jon Cornish fumbled an exchange with quarterback Kevin Glenn to give Toronto the ball on the Stampeders 45.
Toronto increased its lead to 14-3 when Horne intercepted Glenn and returned it 25 yards for the score only 43 seconds into the second quarter. It was Horne's first TD of the year.
"We didn't start well. We didn't take advantage of their turnover and they got two touchdowns on theirs," Stampeders coach John Hufnagel said. "But the bottom line was that we didn't get the ball into the end zone until the game was out of reach."
Swayze Waters kicked a 16-yard field goal for the Argonauts before Paredes connected again to make it 17-6. But Toronto struck right back on Inman's touchdown with 20 seconds left in the half, putting the Argos in control at the break.
Toronto then put the game away on Ray's 7-yard TD pass to Durie with 5:22 left in the game.
"I don't know what this wins says. All I know is we're the 100th Grey Cup champions and no one can take that away from us," Argos coach Scott Milanovich said.
Argos defensive tackle Adriano Belli, who intends to retire for a second time after the Grey Cup, was ejected in the third quarter for unnecessary roughness.