As rare as it is for a late-round NHL draft pick to become a bona fide star, it is even more unusual that he would become a star at two positions. Byfuglien is that rare player, and he has delivered high-level play as a forward and a defenseman in the NHL.

An eighth-round pick (No. 245) of the Chicago Blackhawks in the 2003 NHL Draft, the Minneapolis-born Byfuglien is an intimidating presence at 6-foot-5 and 265 pounds. Despite his linebacker-sized frame, Byfuglien is an above average skater who can take opponents off their games with his big shot, big body and big hockey IQ.

Byfuglien's 25-game run in the 2005-06 NHL season began with a game-winning goal for Chicago in his NHL debut against the Nashville Predators on March 1, 2006. Still playing defense, he appeared in nine games with the Blackhawks during the 2006-07 season.

On Nov. 3, 2007, he arrived for good in the NHL, scoring the opening goal of a 3-2 Chicago win against the St. Louis Blues. Byfuglien scored his first NHL hat trick as part of a four-point night against the Phoenix Coyotes on Nov. 30, 2007 and, while shifting from defense to forward, finished the 2007-08 season fifth on the Blackhawks in goals (19) and tied for second with seven power-play goals and four game-winning goals. 

The following season Byfuglien led Blackhawks forwards with 169 hits and finished tied for seventh with 15 goals. In his Stanley Cup Playoff debut, he scored three goals and nine points while appearing in all 17 of Chicago's postseason games. 

After spending most of the 2009-10 season as a defenseman, Byfuglien tied for the team lead with 11 playoff goals as Chicago won the 2010 Stanley Cup. Byfuglien's postseason included a hat trick in Game 3 of the Western Conference Semifinals against the Vancouver Canucks; a two-goal, four-point effort in Game 5 of the Stanley Cup Finals; and a goal in Chicago's Cup-clinching victory against the Philadelphia Flyers on June 9, 2010.

The Thrashers acquired Byfuglien in a trade on June 24, 2010, and kept him on defense for the 2010-11 season. He responded by leading all NHL defenseman with 20 goals and finishing fourth among NHL defensemen with 53 points. 

Byfuglien played in his first NHL All-Star Game that year to begin a run as a dominant offensive force among NHL defensemen. After a brief switch back to forward in the second half of the 2013-14 season, Byfuglien returned to defense in 2014-15 and was an All-Star selection for a second time while helping the Jets reach the playoffs for the first time since their relocation to Winnipeg. 

On Feb. 8, 2016, the Jets signed Byfuglien to a five-year contract extension.