Harrington was born on March 10, 1993, in Kingston, Ontario,[2] to parents Pat and Cindy.[3] His younger sister Holly also played ice hockey growing up.[4]
On July 1, 2015, Harrington was traded to the Toronto Maple Leafs in a multi-player blockbuster deal for Phil Kessel.[6] Following the trade, Harrington impressed at the Maple Leafs' training camp, making the NHL roster for the opening night of the 2015–16 season. However, injuries plagued Harrington's season, and he would only play 32 games collectively for the Maple Leafs and their American Hockey League (AHL) affiliate, the Toronto Marlies.
Columbus Blue Jackets
On June 25, 2016, shortly after the conclusion of the 2016 NHL Entry Draft, Harrington was traded to the Columbus Blue Jackets (alongside a conditional fifth-round draft pick) in exchange for forward Kerby Rychel. The condition of the fifth-round pick would have been satisfied if Harrington was placed on waivers and claimed during the 2016–17 season, which did not occur.[7]
During the 2017–18 season, Harrington earned consistent playing time after Ryan Murray was injured, resulting in his playing 24 consecutive games. As a result, he also set a career-high with two goals and three assists for five points while also averaging 13:24 per game.[8] Prior to the start of the 2018–19 season, Harrington suffered an upper body injury in a preseason game on September 28 and missed the Blue Jackets first two regular season games.[9] Upon returning to the lineup, Harrington set new career highs in assists and points with two goals and 15 assists for 17 points in a career-high 73 games.[2] He also helped the Blue Jackets advance past the first round of the postseason for the first time in franchise history by recording four assists through 10 playoffs games.[10]
Harrington was a consistent healthy scratch during the 2019–20 season, sitting out 22 of 30 games by December.[11] However, as a result of injuries to the Blue Jackets lineup, he suited up for 39 of the team's 70 regular-season games. Harrington finished the regular season with one goal and seven assists for eight points.[12]
San Jose Sharks
After six seasons within the Blue Jackets organization, Harrington left as a free agent and went un-signed over the summer. On September 9, 2022, Harrington agreed to join the training camp of the San Jose Sharks on a professional tryout.[13] During the pre-season, Harrington successfully completed his tryout in earning a one-year, two-way contract with the Sharks on September 30.[14]
Anaheim Ducks
On February 26, 2023, Harrington was traded to the New Jersey Devils in a multi-player trade, which involved Timo Meier.[15] However, Harrington was waived by New Jersey one day later, and was subsequently claimed by the Anaheim Ducks on February 28.[16][17]
Remaining unsigned through the following summer, on August 23, 2023, the Ducks signed Harrington to a professional tryout (PTO) contract.[18] After attending training camp, Harrington was re-assigned to continue his tryout with the Ducks AHL affiliate, the San Diego Gulls. On October 13, he was signed by the Gulls to a PTO contract to open the 2023–24 season.[19]
ZSC Lions
Before making an appearance with the Gulls, Harrington was released from his tryout on October 14, 2023,[20] and then signed a one-year contract abroad with Swiss club, ZSC Lions of the National League (NL), on October 17.[21] In his lone season with the Lions, Harrington was limited through injury to just 14 regular season games. He returned for the playoffs, helping the club claim the Swiss championship with 2 assists through 6 appearances.
Springfield Thunderbirds
As a free agent, Harrington opted to return to North America and signed a one-year AHL contract with the St. Louis Blues primary affiliate, the Springfield Thunderbirds, on July 12, 2024.[22]