2008-09: Colin Smith made his WHL debut, skating in 12 games for Kamloops, after being selected in the first round (seventh overall) of the 2008 WHL Bantam Draft. In eight regular season games he had 4 assists and was an even plus/minus with 4 penalty minutes. He played in all four games in the Blazers first round playoff series with Kelowna; scoring 1 goal and finishing minus-three. Smith was the leading scorer for CAC Gregg Distributors in the Alberta Midget Hockey League, scoring 23 goals with 32 assists in 33 games. In five playoff games he scored 3 goals with 4 assists.
2009-10: Smith skated in 48 games for Kamloops in his first full WHL season and represented Canada Pacific in the 2010 U17 World Hockey Challenge. He scored 5 goals with 21 assists and was minus-18 with 46 penalty minutes. The Blazers finished third in the B.C. Division and reached the WHL playoffs – falling to Vancouver in a first-round series. In four playoff games Smith scored 2 goals with 2 assists and was minus-one with 2 penalty minutes. In five games for Canada Pacific he scored 1 goal with 3 assists and had 4 penalty minutes.
2010-11: Smith was the second-leading scorer for Kamloops and represented Canada at the 2012 U18 World Junior Championship after the Blazers failed to reach the WHL playoffs. In 72 games he scored 21 goals with 29 assists and had 61 penalty minutes. Smith's minus-21 plus/minus was indicative of the Blazers struggles as Kamloops finished last in the B.C. Division. In seven games for Team Canada he scored 2 goals with 1 assist and was an even plus/minus with 14 penalty minutes. Smith was ranked 96th amongst North American skaters in Central Scouting's final rankings but was not selected in the 2011 NHL Draft.
2011-12: Smith had a breakout year offensively in his third season with Kamloops as the Blazers went from last to first in the B.C. Division under second-year coach Guy Charron. Smith played all 72 regular season games and was Kamloop's second-leading scorer with 35 goals and 50 assists. He was an impressive plus-31 with 51 penalty minutes. After finishing with the WHL's third-best record, the Blazers reached the second round of the playoffs. In 11 playoff games Smith scored 3 goals with 7 assists and was minus-five with 12 penalty minutes. Not among the 210 North American skaters in Central Scouting's final rankings, Smith was selected by Colorado in the seventh round (192nd overall) of the 2012 NHL Draft.
2012-13: Smith was tied for fourth in the WHL with 106 points in his fourth season with Kamloops. Playing on one of the league's top scoring lines along with prospects Tim Bozon (Montreal) and J.C. Lipon (Winnipeg), he led the Blazers with 41 goals and 65 assists in 72 games and was +33 with 72 penalty minutes. Kamloops finished first in the B.C. Division for the second year in a row and reached the Western Conference finals. Smith scored 2 goals with 12 assists and was +2 with 2 penalty minutes in 12 playoff games. He signed a three-year entry-level contract with Colorado in July 2013.