2010-11: Reid Duke played in six games for the CRAA Gold minor midget AAA team as a 15-year-old and had 64 points in 30 games for the Calgary Royals bantam AAA team. He scored 5 goals with 4 assists and 4 penalty minutes playing with CRAA Gold. Duke played for the Calgary South Flames in the Alberta Cup and scored 2 goals with 3 assists and 2 penalty minutes. Duke was the fifth player taken in the 2011 WHL Bantam Draft; selected in the first round by Lethbridge.
2011-12: Duke played in 12 WHL games in five stints with Lethbridge during the season — making his debut with the Hurricanes as a 15-year-old in October — before joining the Hurricanes for good in March. He was a point-per-game scorer for the midget AAA Calgary Royals. Duke scored 2 goals with 4 assists and was +1 with eight penalty minutes skating for Lethbridge, which finished last in the Central Division. Duke scored 13 goals with 16 assists and 24 penalty minutes in 26 games for the Royals. Duke played for first-place Team Alberta in the 2011 Western Canada Challenge Cup U16 tournament, scoring 2 goals with 1 assist, and skated for Canada in the 2012 Youth Winter Olympics Game. He scored 3 goals with 2 assists and was -2 with 4 penalty minutes in six games for the Canada U16 team.
2012-13: Duke skated in 57 games for the Hurricanes in his first WHL season — missing time in December with an upper body injury — and played for Canada Pacific in the 2013 U17 World Hockey Challenge. He scored 8 goals with 16 assists and was +8 with 30 penalty minutes. The Hurricanes missed the playoffs; finishing last in the powerful Central Division. He scored 2 goals with 3 assists in five games at the WHC for silver medal-winning Canada Pacific.
2013-14: Duke was the third-leading scorer for a Lethbridge team that had the WHL’s worst record. He scored 15 goals with 25 assists and was -47 with 91 assists in 62 games; missing time mid-season due to an upper body injury. Lethbridge won just 12 games . Duke was ranked 65th amongst North American skaters in Central Scouting’s mid-term rankings prior to the 2014 NHL Draft.