Kontiola had 15 goals and 37 points in 53 games with Traktor Chelyabinsk in the Kontinental Hockey League last season, and nine points in 10 games for Finland, which won the silver medal at the 2014 IIHF World Championship. He had five points in six games to help Finland win the bronze medal at the 2014 Sochi Olympics.
Sportsnet reported Kontiola had to negotiate a buyout of his KHL contract before signing with the Maple Leafs.
The 29-year-old was a seventh-round (No. 196) pick of the Chicago Blackhawks in the 2004 NHL Draft, and his only NHL experience came in 12 games with the Blackhawks during the 2007-08 season. He spent the following season in the American Hockey League, and has been playing in Russia since the 2009-10 season.