2008-09: Karl Stollery skated in 35 games for Merrimack College as a freshman. He scored 5 goals with 11 assists and was -1 with 28 penalty minutes. Merrimack slipped to ninth place in Hockey East but played some of its best hockey late in the year – finishing 4-4-1 in its last nine games. Stollery was named to Hockey East's All-Rookie team.
2009-10: Stollery played in 35 games in his sophomore season at Merrimack. He was the Warrior's fourth leading scorer and topped Merrimack defensemen with 4 goals and 15 assists and was -2 with 42 penalty minutes. Merrimack finished sixth in Hockey East and took third place Boston University to a decisive third game in the Hockey East quarterfinals.
2010-11: Stollery was the leading scorer amongst Merrimack defensemen for the second straight year in the Warriors' most successful season since joining Hockey East in 1989-90. The junior was an assistant captain and scored 6 goals with 21 assists in 39 games; finishing +11 with 48 penalty minutes. Merrimack finished fourth in Hockey East and earned an at-large bid to the NCAA tournament after reaching the Hockey East championship game. The Warriors lost 4-3 in overtime to Notre Dame in the NCAA Northeast semifinals to finish 25-10-4.
2011-12: Stollery made his pro hockey debut with the AHL's Lake Erie Monsters in March following his senior season at Merrimack. In nine games he scored 2 goals with 5 assists and was an even plus/minus with 4 penalty minutes. The Monsters finished third in the North Division, one point behind Rochester and Houston for the final Western Conference playoff spot. Stollery was a team captain in his final college season and led Merrimack defensemen with 21 points. He scored 7 goals with 14 assists in 37 games and was +13 with 58 penalty minutes. The Warriors, finished fifth in Hockey East, posting back-to-back winning seasons for the first time since joining the conference, but did not receive an NCAA bid after falling to Maine in a three-game Hockey East quarterfinal series.
2012-13: Stollery played in 72 games for Colorado AHL affiliate Lake Erie in his first pro season, most amongst Monsters' defensemen. He scored 5 goals with 29 assists to lead Lake Erie defensemen in points and was +11 with 62 penalty minutes. The Monsters finished third in the North Division but missed the Western Conference playoffs. Stollery signed a one-year free agent contract with Colorado in May, 2013.
Stollery signed a one-year entry-level contract in May, 2013.