The 6-1, 191-pound goaltender appeared in 63 career games for the Rangers, posting a 20-32-4 record, along with a 3.22 goals against average and a .894 save percentage. In 2001-02, he became the fifth youngest goaltender in NHL history and second youngest in franchise history to appear in a NHL contest on October 10 (18 years, 143 days). Blackburn recorded his first professional victory on October 15 at Montreal, becoming the third youngest goaltender in NHL history and second youngest in Rangers history to record a NHL win (18 years, 148 days). He participated in the 2001 Topps/NHL YoungStars Game at the 52nd annual NHL All-Star Game in Los Angeles on February 2 and was named to the 2001-02 NHL All-Rookie Team at the conclusion of the season. During the 2002-03 season, Blackburn became just the fourth goaltender in NHL history to start 15-or-more consecutive games as a teenager when he made 18 consecutive starts from November 7 through December 14.

Prior to joining the Rangers, Blackburn had a highly successful junior career with the Kootenay Ice of the Western Hockey League. He appeared in 101 career WHL contests with the Ice, posting a 67-22-9 record, along with a 2.65 goals against average. During the 1999-2000 season, Blackburn was named Rookie of the Year for both his team and the WHL and was also selected to the CHL All-Rookie Team.

In 2000-01, he led the WHL in wins with 33, ranked second in the league with a .907 save percentage and third with a 2.77 goals against average. In 11 post-season contests, Blackburn registered a 7-4 record, along with a 1.95 goals against average en route to being named the 2001 WHL Playoff MVP. In addition, he was selected as the WHL Goaltender of the Year and the Canadian Hockey League (CHL) Goaltender of the Year.