During the 2015–16 season, Carr became one of only a few NHL players to score a goal on the first shot during the first shift of their NHL debut on November 29, 2015 in a game versus the Carolina Hurricanes.[3] He re-signed with the Canadiens on July 1, 2016.[4]
On July 1, 2018, Carr signed a one-year, $750,000 deal with the Vegas Golden Knights after not receiving a qualifying offer from the Canadiens.[5] In the 2018–19 season, Carr won the Les Cunningham Award as league MVP while he was assigned to the Golden Knights American Hockey League (AHL) affiliate, the Chicago Wolves. He recorded a career-best 30 goals and 41 assists for 71 points in just 52 games. He was recalled through the season to feature in six games for Vegas, registering a goal. In returning to the Wolves for the 2019 Calder Cup playoffs, Carr recorded 12 points in 15 games before falling in the Finals to the Charlotte Checkers.
On September 5, 2020, as a free agent from the Predators, Carr signed a three-month contract through November 15 by HC Lugano of the National League (NL) as a replacement for injured forward Jani Lajunen.[7] At the opening of free agency, he was signed by the Washington Capitals to a one-year, two-way contract on October 12, 2020. Due to the ongoing COVID-19 pandemic, Carr remained in Switzerland with Lugano until the commencement of the Capitals' training camp.[8]
In the 2020–21 season, Carr served the majority of his tenure with the Capitals as a healthy scratch, registering an assist in six regular season games and drawing into a first-round playoff contest against the Boston Bruins.
As an impending free agent, Carr opted to return to Switzerland, rejoining HC Lugano on a one-year contract in July 2021.[9] Shortly thereafter, he agreed to a three-year extension with the team on January 1, 2022.[10]