Tellqvist was drafted 70th overall by the Toronto Maple Leafs in the 2000 NHL Entry Draft. He had played a total of 14 games for the Leafs before the 2005–06 season, spending most of his time with their then American Hockey League affiliate, the St. John's Maple Leafs. In 2003, Tellqvist played in the world hockey championship. Here is where he represented Sweden. During this time he recorded a 1.37 goals against average and a.940 save percentage. But unfortunately the run came to an end when they played Canada in the finals. They would lose and capture silver. At the end of the 2005–06 season, when starting Maple Leafs goaltender Ed Belfour was injured, Tellqvist played in two consecutive games against the Montreal Canadiens when the Leafs were struggling to make the playoffs near the end of the season. He struggled in those games, letting in 11 total goals. Following the second game, he was replaced by Toronto's third-string goaltender, Jean-Sébastien Aubin. On November 28, 2006, Tellqvist was traded to the Phoenix Coyotes in exchange for forward Tyson Nash and a fourth-round draft pick in 2007 NHL Entry Draft. Later in the season, on February 16, 2007, the Coyotes signed him to a contract extension through to the 2007–08 season. On March 12, 2007, in a game against the Philadelphia Flyers, he stopped all 24 shots to record his fourth career NHL shutout. On April 3, 2007, he set a new career high in wins with 11. For the 2007–08 season, Tellqvist competed for Phoenix's starting goaltender position with Alex Auld and David Aebischer. Aebischer was eventually waived, setting up the tandem of Tellqvist and Auld. Upon the acquisition of Ilya Bryzgalov via waivers from the Anaheim Ducks, Auld was eventually traded to the Boston Bruins; Tellqvist became the back-up behind Bryzgalov. On March 4, 2009, Tellqvist was traded by the Coyotes to the Buffalo Sabres in exchange for a fourth-round draft pick in 2010. On May 1, 2009, Tellqvist signed with Ak Bars Kazan of the Kontinental Hockey League for the 2009–10 season. On November 19, 2009, Tellqvist was traded to Lukko in the Finnish SM-liiga. Lukko was at the time leading the League by 18 points, and is one of the leading candidates for the championship. On August 4, 2010, it was announced that Tellqvist has signed with Dinamo Riga of the KHL for the 2010–11 season. On November 2, 2017, Tellqvist officially announced his retirement as a player.
