Campbell played three seasons of major junior hockey with the Sault Ste. Marie Greyhounds of the Ontario Hockey League. Campbell began his professional career playing for the Manchester Monarchs of the American Hockey League during the 2008–09 AHL season. On July 3, 2012 he was signed by the Los Angeles Kings to a two-year Entry-level contract. On April 5, 2014, after playing 444 games in the AHL, Campbell finally made his NHL debut to skate 14:41 with the Los Angeles Kings in a 2-1 loss against the Vancouver Canucks. After spending the first six years of his professional career entirely within the Kings organization, Campbell left as a free agent to sign a one-year contract with the Arizona Coyotes on July 1, 2014. In the 2014–15 season, Campbell was originally assigned to AHL affiliate, the Portland Pirates. Campbell would later be recalled and remained in the NHL for the duration of the season with the lowly Coyotes, appearing in 33 games from the blueline. Despite experiencing a break through season in the NHL, Campbell was unable to attract an NHL offer as a free agent and on July 3, 2015, was signed to a one-year AHL contract with the Toronto Marlies. Later that year, on September 29, Campbell signed a two-year, two-way contract with the Marlies' parent club, the Toronto Maple Leafs. He was reassigned to continue with the Marlies, and was later named team captain. In an article from the Sachem.ca, published April 5, 2016, Campbell cited his multi-sport childhood as a main driver of his success in professional hockey. "I played a lot of golf and baseball. Many of the skills in those sports cross over with hockey. My neighbours also possessed more talent than I did in baseball-based games such as pickle and tennis-ball home-run derbies, so consistently losing to them only made me work harder to become a better athlete." On July 1, 2017, having left the Maple Leafs as a free agent, Campbell agreed to a return with the Arizona Coyotes in signing a two-year, two-way contract. On July 12, 2018, Campbell was part of a multi-player trade by the Coyotes along with Marcus Krüger, Jordan Maletta, prospect MacKenzie Entwistle, and a fifth-round pick in 2019 to the Chicago Blackhawks in exchange for the contract of Marián Hossa, Vinnie Hinostroza, Jordan Oesterle, and a third-round pick in 2019.
