2008-09: Stuart Percy played for the Toronto Marlboros in the GTHL. He was chosen in the first round, 15th overall, of the 2009 OHL Priority Selection by the Mississauga St. Michael’s Majors.
2009-10: In his OHL rookie season, Percy played in 52 games for the Majors. He scored 3 goals and added 15 assists for 18 points. Percy registered 1 assist in 16 playoff games. Percy played for Team Ontario at the 2010 World U-17 Hockey Challenge, picking up 3 assists in 6 games for the silver medal squad.
2010-11: In 64 games for the Majors, Percy scored 4 goals and added 29 assists for 33 points to go along with 50 penalty minutes. In 20 playoff games, he scored 2 goals and added 10 assists for 12 points. Percy registered 4 assists in 5 Memorial Cup Tournament games for the Majors. Percy played for Team Orr at the 2011 CHL Home Hardware Top Prospects Game.
2011-12: Percy made his pro debut — appearing in one regular season game and three playoff contests for the AHL’s Toronto Marlies — following an injury-filled third junior season that included two concussions and an October knee injury. He had an assist in his AHL debut on April 15th against Adirondack and played all three games in the first round series with Rochester; finishing plus-one with no points nor penalties. Limited to 34 games during the regular season for Mississauga St. Michael’s, he scored 5 goals with 25 assists and was plus-18 with 41 penalty minutes. The Majors reached the playoffs after finishing fifth in the Central Division. Percy was minus-two in the six-game series with Barrie; scoring 1 goal with 1 assist and getting 4 penalty minutes.
2012-13: Percy returned to Mississauga for his fourth OHL season — skating for the re-christened Steelheads — and finished the season in the AHL playing for the Toronto Marlies. In four AHL games he scored 1 goal with 2 assists and was -1 with 2 penalty minutes. Toronto finished first in the North Division and reached the second round in the AHL playoffs. Percy did not play in any playoff games. In 68 games with Mississauga he scored 13 goals with 32 assists and was -8 with 44 penalty minutes. The Steelheads reached the playoffs despite finishing last in the Central Division; falling to Belleville in six games. Percy had 2 assists and was -6 with 4 penalty minutes in six playoff games.
Percy possesses all-round capability, and is very calm under pressure situations. He moves the puck efficiently out of the defensive zone and is starting to become a threat offensively – although he is unlikely to develop into a premiere offensive defender. He is still developing his power and skating skills.
Percy made the Maple Leafs out of training camp and was given a long look in October before being assigned to the AHL's Toronto Marlies. Shuffling between the Marlies and Leafs in his second pro season he is expected to be a key force on the Toronto blue line for years to come. To stay at the NHL level on a permanent basis he must continue to add strength and become more consistent in his own end.