The native of Duluth, Minnesota was chosen 35th overall by the Dallas Stars in the 1993 NHL Entry Draft after three excellent seasons with Cloquet High School. Langenbrunner joined the Peterborough Petes of the OHL and accumulated 190 points over two years. In 1995-96, Langenbrunner enjoyed a fine rookie season as a pro with 25 goals in 59 games for the IHL's Michigan K-Wings and a 12-game recall to the NHL.
A two-time member of the U.S World Junior team (1994-1995), Langenbrunner became a regular in 1996-97 and contributed 13 goals while working diligently to improve his defence. He scored 23 goals the next year and represented the U.S. at the Nagano Olympics. By the 1998-99 season, Langenbrunner was an exemplary forechecker and penalty killer who was often assigned to shadow the best players on the opposition. In the post-season, he scored ten goals while helping the Stars win the first Stanley Cup in franchise history.
During the 2000 and 2001 seasons, Langenbrunner continued to be an effective checker but his offence dropped off. The Stars were defeated by New Jersey in the Stanley Cup finals in 2000 and watched the Colorado Avalanche claim hockey's ultimate prize the next year. After the Stars added centre Pierre Turgeon in the off-season, Langenbrunner's role on the team swung even more into the realm of defence and was later traded along with Joe Nieuwendyk to the New Jersey Devils.
With his arrival in New Jersey, Langenbrunner rediscovered his offensive prowess. He led the Devils in scoring during the 2002-03 regular season with a career high 55 points on 22 goals and led all playoff scorers with 11 goals and 18 points in aiding the Devils to a Stanley Cup title. Coming off a career year offensively in 2002-03, injuries limited Langenbrunner to a mere 55 games in 2003-04.
Langenbrunner's all-around solid play made him a natural leader in New Jersey. As such he was selected the club's captain in 2008. Still providing dependable play in his own end, 2008-09 saw Langenbrunner near the 30-goal plateau for the first time. He would finish the year with 29, setting a new career-high.
In February of 2010, Langenbrunner was captain of the US Olympic team that brought home the silver medal in a thrilling overtime final at the Olympic Winter Games in Vancouver.
On January 7, 2011, Langenbrunner's time in New Jersey would come to an end. He was traded back to the Dallas Stars, the club that had drafted him in 1993, in exchange for a conditional draft pick.
In the summer of 2011, Langenbrunner was on the move again. This time, as an unrestricted free agent, he inked a deal with the St. Louis Blues.