Oshie started his career in the greater Seattle area, playing for Seattle Junior Hockey Association.
 Then moved to Warroad, Minnesota when he was a bantam.
 Following his draft, Oshie played for the University of North Dakota men's ice hockey team in the Western Collegiate Hockey Association (WCHA) for three seasons.
Scoring a team-leading 24 goals as a freshman, he added 21 assists for 45 points total.
He also set a school record with nine game-winning goals in the season, which also led all NCAA players.
At the end of his debut season, he was named to the WCHA All-Rookie Team and the WCHA Final Five All-Tournament Team.

In his sophomore year, Oshie improved to 52 points (17 goals and 35 assists), ranking second in team scoring.
He earned Third Team All-WCHA and received the Fighting Sioux's Cliff "Fido" Purpur Award, given to the player who demonstrates hard work and determination while generating excitement on the ice.
Following North Dakota's WCHA playoff run, Oshie led all players with eight points (four goals and four assists) in the 2006 NCAA Tournament, earning NCAA West All-Tournament honors.
He played his last season with North Dakota as a junior, recording 45 points in 42 games.
Oshie started his career in the greater Seattle area, playing for Seattle Junior Hockey Association.  Then moved to Warroad, Minnesota when he was a bantam.  Following his draft, Oshie played for the University of North Dakota men's ice hockey team in the Western Collegiate Hockey Association (WCHA) for three seasons. Scoring a team-leading 24 goals as a freshman, he added 21 assists for 45 points total. He also set a school record with nine game-winning goals in the season, which also led all NCAA players. At the end of his debut season, he was named to the WCHA All-Rookie Team and the WCHA Final Five All-Tournament Team.
In his sophomore year, Oshie improved to 52 points (17 goals and 35 assists), ranking second in team scoring. He earned Third Team All-WCHA and received the Fighting Sioux's Cliff "Fido" Purpur Award, given to the player who demonstrates hard work and determination while generating excitement on the ice. Following North Dakota's WCHA playoff run, Oshie led all players with eight points (four goals and four assists) in the 2006 NCAA Tournament, earning NCAA West All-Tournament honors. He played his last season with North Dakota as a junior, recording 45 points in 42 games.
T. J. Oshie