Anaheim Ducks, brief stint in Atlanta and return to Anaheim

Kunitz was originally signed as an undrafted free agent by the Mighty Ducks of Anaheim on April 1, 2003. He split his professional rookie season between Anaheim and their American Hockey League (AHL) affiliate, the Cincinnati Mighty Ducks. After spending the 2004–05 NHL lock-out with Cincinnati, he was picked up on waivers by the Atlanta Thrashers in 2005–06. Two weeks later, however, he was re-claimed off waivers by the Ducks and went on to play 67 games with them, scoring 19 goals and adding 22 assists for 41 points, surpassing Paul Kariya's club record 39-point rookie season in 1994–95 (Kunitz still qualified as a first-year player because he did not play the minimum required games with Anaheim in 2003–04 to register as his NHL rookie season; the record was broken the following season by Dustin Penner's 45 points).

In the 2006–07 NHL season, Kunitz improved to 25 goals and 60 points. He went on to help the Ducks advance through the playoffs, past the Minnesota Wild, Vancouver Canucks, and Detroit Red Wings, en route to a Finals victory against the Ottawa Senators to capture both his and the franchise's first Stanley Cup championship. Kunitz had been injured during the semi-finals against the Red Wings, but returned late in the Stanley Cup Finals against Ottawa to help clinch the championship in game five.

The next season, in 2007–08, Kunitz was named one of the team's alternate captains, his first time with the Ducks and his professional career. In regards to Kunitz' new position, Ducks head coach Randy Carlyle explained, "Rob Niedermayer was an alternate last year and did a fine job, and we thought it was important to involve our younger players in the leadership role. Chris Kunitz fit that role."."^[2] Kunitz's production dipped to 50 points that season.

Pittsburgh Penguins

In the midst of another slow season in 2008–09, he was traded to the Pittsburgh Penguins along with prospect Eric Tangradi for defenceman Ryan Whitney. The move was also precipitated by a need for secondary scoring on the Penguins behind Sidney Crosby and Evgeni Malkin. During the 2009 playoffs, he recorded 1 goal and 13 assists as the Pittsburgh Penguins won the Stanley Cup in a rematch of the previous year's Stanley Cup Finals against the Detroit Red Wings, giving Kunitz his second championship in three years.

On November 6, 2010, Kunitz played his 400th career game and recorded a goal in that game against the Phoenix Coyotes. On March 15, 2016, he played his 800th career game and recorded a goal against the New York Islanders.^[3] In the 2016 Playoffs, he recorded 4 goals and 8 assists for 12 points, as the Penguins went to defeat the San Jose Sharks in six games in 2016. It would be Kunitz's third Stanley Cup of his career, his second with the Pens. Since 2010, he has been a regular member of the Penguins' top lines with Evgeni Malkin and/or Sidney Crosby. On May 25, 2017, Kunitz sent the Penguins to the Stanley Cup Finals with a double overtime game winner in Game 7 of the Eastern Conference Finals versus the Ottawa Senators. This would later become Kunitz's last career playoff goal. He became the oldest player to score a game 7 playoff series winning goal at the age 37. The Penguins faced off against the Nashville Predators in the 2017 Finals, defeating them in six games to successfully defend the Stanley Cup, with Kunitz assisting on the series-winning goal. This marked Kunitz's fourth Stanley Cup of his career, and his third as a member of the Penguins.^[4]

Tampa Bay Lightning

On July 1, 2017, Kunitz left the Penguins as a free agent and signed a one-year, $2 million, contract with the Tampa Bay Lightning.^[5] The Lightning announced through its social media account that Kunitz would wear the #14.^[6] Kunitz had previously worn the number with the Penguins and the Ducks. Kunitz recorded 13 goals and 29 points during the season, but just one assist in the playoffs as the Lightning lost in the Eastern Conference Final to the eventual champion Washington Capitals in 7 games.

Chicago Blackhawks

On July 1, 2018, Kunitz signed a one-year, $1 million contract with the Chicago Blackhawks. He played 56 games and had 5 goals and 10 points.^[7]

On July 30, 2019, Kunitz announced his retirement from professional hockey after 15 seasons. He joined the Blackhawks' organization as a player development adviser as well as the coaching staff of their American League affiliate, the Rockford IceHogs.^[8]