2010-11: Kyle Jenkins played for the Mississauga Rebels bantam AAA team in Ontario.
2011-12: Jenkins skated for the Mississauga Rebels minor midget AAA team. In 67 games he scored 13 goals with 28 assists and had 36 penalty minutes. He scored 1 goal in seven games for the Rebels at the 2012 OHL Cup. Jenkins was selected by Sault Ste. Marie in the fourth round (68th overall) in the 2012 OHL Priority Draft.
2012-13: Jenkins made his OHL debut in March — appearing in a late-season game with Sault Ste. Marie — after skating for the junior A Oakville Blades in the Ontario Junior Hockey League. He had no points nor penalty minutes and was -2 in his only game with the Greyhounds. Jenkins was named to the OJHL's All-Prospect first team; scoring 9 goals with 20 assists and 47 penalty minutes in 46 games. He scored 1 goal with 2 assists and 16 penalty minutes in six playoff games.
2013-14: Jenkins skated in 63 of 68 regular season games for the Sault Ste. Marie Greyhounds in his first OHL season. He scored 7 goals with 18 assists and was +6 with 28 penalty minutes. The Greyhounds finished first in the West Division with the OHL's fourth-best record. Jenkins was ranked 75th amongst North American skaters in Central Scouting's mid-term rankings prior to the 2014 NHL Draft.