2009-10: After being selected by Portland in the second round (24th overall) of the 2009 WHL Bantam Draft, Taylor Leier skated in 41 games for the Saskatoon Contacts in the Saskatchewan Midget AAA Hockey League. In his first season with the Contacts he was the team's third-leading scorer with 17 goals and 24 assists and had 30 penalty minutes. After finishing first in the regular season, Saskatoon lost to the Notre Dame Hounds in the playoff finals. In 11 playoff games Leier scored 5 goals with 2 assists.
2010-11: Leier spent a second season with the Contacts and was the SMHL's second-leading scorer. In 44 games he scored 31 goals with 43 assists and had 32 penalty minutes. The Contacts had the same amount of points as league-leading Prince Albert (67) but finished second as the Mintos had one fewer overtime loss. Prince Albert swept a best-of-five playoff finals series with the Contacts after Saskatoon had won its first six playoff games. In nine playoff games Leier was Saskatoon's second-leading scorer with 7 goals and 6 assists. He was named a first team SMHL All-Star.
2011-12: Leier skated in all 72 regular season games for the powerful Portland Winterhawks in his first season in the WHL. He scored 13 goals with 24 assists and was plus-11 with 36 penalty minutes. After finishing second in the U.S. Division, two points behind Tri-City, Portland reached the WHL Finals against the Edmonton Oil Kings. Leier was an even plus/minus in 22 playoff games and scored 5 goals with 2 assists. Ranked 131st among North American skaters in Central Scouting's final rankings prior to the 2012 NHL Draft, Leier was selected by Philadelphia in the fourth round (117th overall).
2012-13: Leier scored at nearly a point-per-game pace for the WHL champion Portland Winterhawks in his second junior season. Overshadowed playing on a team with the league's top three scorers, he had 27 goals with 35 assists in 64 games and was +41 with 63 penalty minutes. Portland finished first in the U.S. Division and reached the WHL finals for the third straight season. Leier scored 9 goals with 7 assists and was +11 with 12 penalty minutes in 21 playoff games as the Winterhawks captured the first WHL title in club history. Leier scored 1 goal with 2 assists and was +3 in three Memorial Cup games — missing the final two games of the tournament after suffering a head injury on a hit from Saskatoon's Dalton Thrower.
Leier has returned to the WHL to captain the Portland Winterhawks in 2013-14.