He has previously played with the Pittsburgh Penguins, Chicago Blackhawks, Toronto Maple Leafs, and Vancouver Canucks.

[3] After attending a skating clinic run by Dave, Lafferty and his younger brother Charlie played for the Mid-State Mustangs and the Altoona Trackers of the Pittsburgh Area Hockey League.

[4] During the 2013–14 season, Lafferty tallied a career-best 21 goals and 34 assists for 55 points in 25 games and was named to the 2014 Prep School All-New England team.

[12] He was also named Team MVP and selected as a semifinalist for the Walter Brown Award as the best American-born college hockey player in New England.

[15] Following this, Lafferty was named the ECAC Player of the Week in February after he recorded four points in two games to help Brown to sweep Harvard and Dartmouth.

[19] On March 7, 2018, Lafferty concluded his collegiate career by signing an amateur tryout agreement with the Wilkes-Barre/Scranton Penguins of the American Hockey League (AHL) for the remainder of the 2017–18 season.

[20] He also signed a two-year, entry-level contract with the Pittsburgh Penguins of the National Hockey League (NHL) that began in the 2018–19 season.

[27] At the end of the Maple Leafs 2023 training camp, Lafferty was traded to the Vancouver Canucks for a fifth-round selection in the 2024 NHL entry draft on October 8, 2023.

[29] Unable to agree to terms with the Blackhawks, on July 1, 2024, Lafferty signed as a free agent to a two-year, $4 million contract with the Buffalo Sabres.