2008-09: Josh Leivo skated for the Barrie Junior Colts (midget AAA) and was selected by Sudbury in the 11th round (205th overall) of the 2009 OHL Priority draft.
2009-10: Leivo scored 30 goals playing with the Barrie Junior Colts AAA club.
2010-11: Leivo signed with Sudbury after attending the Wolves summer camp. After a slow start to his rookie season – he did not have a point until his sixth game (scoring twice in an October game against Niagara Falls) and did not score again until December – Leivo's game picked up in the second half after he was placed on a line with San Jose prospect Michael Sgarbossa and Russian import forward Andrey Kuchin. Leivo finished the regular season with 13 goals and 17 assists and 37 PMs in 64 games. Remarkably, after being -25 plus/minus on January 2, Leivo was +15 in his last 29 games. Leivo was at his best in the playoffs as the Wolves, after finishing below .500 in the regular season, swept the East Division champion Ottawa 67's in the first round before falling to Central Division winner and eventual playoff finalist Mississauga St. Mike's in the second round. In the first playoff game at Ottawa, Leivo had a hat trick and two assists in a wild, 8-7, Wolves' win. In eight playoff games he scored 6 goals with 7 assists and was +6 with 4 PMs. Not among the North American skaters on Central Scouting's final rankings, Leivo was selected by the Toronto Maple Leafs in the 3rd round (86th overall) in the 2011 NHL Draft.
2011-12: Leivo made his pro hockey debut, playing in a late season game for the AHL's Toronto Marlies, after a breakout offensive year with the Sudbury Wolves. He was minus-one with no points or penalty minutes in his only game with the Marlies. In his second OHL season he was the Wolves second-leading scorer behind Avalanche prospect Michael Sgarbossa. Leivo scored 32 goals with 41 assists and was plus-two with 61 penalty minutes in 66 games. Sudbury finished fourth in the Central Division. Leivo scored 2 goals with 1 assist and was minus-five with six penalty minutes in the four-game playoff series with Brampton.
2012-13: Leivo signed a three-year entry-level contract with the Maple Leafs in August 2012. He attended Toronto's training camp before returning to Sudbury for his third OHL season. He was traded from Sudbury to Kitchener in January of 2013 and finished the year in the AHL with the Marlies. Leivo had two assists and was +1 in four regular season AHL games for Toronto,which finished first in the North Division and reached the second round. Leivo played three playoff games and was +2 with 1 assist. He was leading Sudbury in scoring at the time he was traded, scoring 19 goals with 25 assists in 34 games, and scored 10 goals with 19 assists and was +6 with 18 penalty minutes in 29 regular season games for Kitchener. The Rangers advanced to the second round, falling to eventual OHL champion London. Leivo scored 3 goals with 9 assists and had an even plus/minus with 8 penalty minutes in 12 playoff games.
Leivo is a naturally gifted athlete who has consistently trended upwards for two seasons now. He can play a variety of roles which makes him a versatility player. His size allows him to work very well down low and he protects the puck effectively. Leivo projects as a top-nine power-forward who can play special teams.
Leivo is scheduled to make his rookie debut with the Toronto Marlies in 2013-14 season.