Cullen was rarely the center of attention but often found himself in the middle of it anyway. He was a pivotal role player for eight teams during an NHL career that ran from 1997 through 2019, capable of leading the power play, killing penalties and winning face-offs.

A native of Virginia, Minnesota, Cullen played at Moorhead High School, where his father, Terry, was coach. The younger Cullen was named The Associated Press High School Player of the Year in the state in 1995 and finished as runner-up for Mr. Hockey honors after scoring 89 points (47 goals, 42 assists) in 28 games.

Following high school, Cullen attended St. Cloud State University and was named to the Western Collegiate Hockey Association All-Rookie team following his freshman year, when he scored 41 points (12 goals, 29 assists) in 39 games.

Cullen was then selected by the Mighty Ducks of Anaheim in the second round (No. 35) of the 1996 NHL Draft. He returned to St. Cloud State for his sophomore season and earned All-WCHA Second Team status following a 45-point season (15 goals, 30 assists in 36 games) before signing with the Mighty Ducks. Cullen made his NHL debut against the Toronto Maple Leafs on Oct. 28, 1997, and scored his first NHL goal against the Florida Panthers on Jan. 21, 1998.

After six seasons with Anaheim, Cullen was traded to the Florida Panthers on Jan. 20, 2003. He played one season with the Panthers before he became a free agent and signed with the Carolina Hurricanes on Aug. 5, 2004. He had a big season in 2005-06 with an NHL career-high 25 goals, then scored 18 points (four goals, 14 points) in the Stanley Cup Playoff games to help the Hurricanes win the Cup, including two assists in a 3-1 victory in Game 7 against the Edmonton Oilers in the Final.

Cullen signed a four-year contract as a free agent with the New York Rangers on July 1, 2006, but after one season was traded back to Carolina. He spent two more full seasons with the Hurricanes before he was traded to the Ottawa Senators for the final 21 games of the 2009-10 season.

A free agent once again at the end of that season, Cullen returned home to play for the Minnesota Wild, signing a three-year contract on July 1, 2010, before joining the Nashville Predators on a two-year contract on July 5, 2013.

Cullen joined his eighth NHL team when he signed with the Pittsburgh Penguins on Aug. 6, 2015. He was brought in to round out the Penguins' bottom two lines as a penalty-killer and face-off specialist, but proved to be more valuable than that: In 2015-16, he scored 32 points (16 goals, 16 assists) in 82 games, won 55.7 percent of his face-offs and scored three shorthanded goals. Cullen then scored six points (four goals, two assists) in 24 playoff games, including two game-winning goals, to help Pittsburgh win the Cup.

In 2016-17, Cullen finished with 31 points (13 goals, 18 assists) in 72 games, then contributed nine points (two goals, seven assists) in 25 playoff games to help the Penguins repeat as Stanley Cup champions. He returned to the Wild in 2017-18, then signed as a free agent with the Penguins for his 21st and final NHL season in 2018-19.

Cullen retired after the 2018-19 season with 731 points (266 goals, 465 assists) in 1,516 NHL games, as well as 58 points (19 goals, 38 assists) in 132 playoff games.