2008-09: Garret Sparks played 18 games for Team Illinois U-16 and was 9-6-2 with a 3.05 GAA and .879 save percentage. Sparks was selected by the Guelph Storm in the 8th round (160th overall) of the OHL Priority Draft and was one of 24 goalies invited to participate in USA Hockey's Warren Strelow national goaltending camp. Sparks attended USA Hockey's U-17 tryout camp.
2009-10: Sparks and goaltending partner Eric Garavaglia combined to lead Chicago Mission to the 2010 USA Hockey Tier 1 U-18 championship. Sparks appeared in 27 games and had a record of 19-7 and 3 shutouts with a 1.98 GAA and .907 save percentage. Sparks was in net for the championship game and stopped 24 of 25 shots in a 7-1 win over the Philadelphia Junior Flyers.
2010-11: Sparks appeared in 19 games as an OHL rookie behind Guelph Storm starter Brandon Foote. Among the season highlights for Sparks were a 38-save, 5-3 win over high-powered Windsor in November (his second OHL start) and a string of games between Jan 23 and Feb 21 when Sparks won six of seven starts. Overall, he finished with a record of 8-6 with one shootout loss and posted a 3.64 GAA with an .890 save percentage. Guelph finished fourth in the Midwest division but Sparks did not see any action in the playoffs as Foote was in net for all six games of the Storm's first-round series loss to Saginaw. Sparks was ranked 17th among North American goaltenders by Central Scouting and was selected by the Maple Leafs in the 7th round (190th overall) of the 2011 NHL Draft.
2011-12: Sparks assumed the lion's share of the goaltending duties for the OHL's Guelph Storm after splitting time with 20-year-old Brandon Foote early in the season. He played a career-high 59 games and was 27-25-4 with 5 shutouts and had a 3.11 goals against and .907 save percentage. Sparks started all six games in the Storm's playoff series with Plymouth and was 2-4 with a 4.45 goals against and .881 save percentage. Sparks participated in USA Hockey's U20 Junior Evaluation Camp in Lake Placid in August, 2012.
Sparks will be minding the net for the Guelph Storm in the 2012-13 season.