Calgary Flames organization and Edmonton Oilers (2013–2018)

On April 4, 2013, the NHL's Calgary Flames signed Brossoit to an entry-level contract.^[7][8] Despite rumours of continuing his successful Memorial Cup season with the Flames for the end of the 2012–13 NHL season, Brossoit was not called-up.^[9]

On November 8, 2013, Brossoit was traded to the Edmonton Oilers.^[10] On March 24, 2014, after playing 30 games in the ECHL with the Bakersfield Condors and eight games in the American Hockey League (AHL) with the Oklahoma City Barons, Brossoit received his first NHL call-up to backup Oilers' starter Ben Scrivens.^[11]

On January 21, 2017, Brossoit earned his first NHL win in a game against the Calgary Flames.^[12]

Winnipeg Jets (2018–2021)

After five seasons within the Oilers organization, Brossoit left as a free agent following the 2017–18 season. On July 1, 2018, he signed a one-year, two-way contract with the Winnipeg Jets.^[13] While playing with the Jets, Brossoit earned his first career NHL shutout in a 1–0 win over the Vancouver Canucks on December 22. He made 40 saves in the win.^[14]

On May 25, 2019, the Jets re-signed Brossoit to a one-year, $1.225 million contract.^[15] He signed another one-year contract on October 2, 2020, this time with a salary of $1.5 million.^[16]

Vegas Golden Knights (2021–2023)

On July 28, 2021, following his third season with the Jets, Brossoit left as a free agent and was signed a two-year, $4.65 million contract with the Vegas Golden Knights.^[17] In his first season with the team, he served as backup to Robin Lehner and recorded a 10–9–3 record and .895 save percentage. However, it was announced that he required hip surgery in the off-season that would leave him unavailable for the beginning of the 2022–23 season.^[18]

Following Brossoit's return from hip surgery, the Golden Knights' management opted to have him begin with the franchise's AHL affiliate, the Henderson Silver Knights.^[19][20] Brossoit was waived by the Golden Knights on November 10, 2022, and cleared waivers the following day.^[21][22] Injuries to both Logan Thompson and Adin Hill eventually prompted Brossoit's recall to the NHL, playing alongside former Los Angeles Kings starter Jonathan Quick, who the team acquired midseason.^[23][24]

The Golden Knights finished first in the Western Conference to qualify for the 2023 Stanley Cup playoffs, with Brossoit named the starting goaltender for their first-round series against the Winnipeg Jets;^[25] Brossoit's starting role against his former team and partner Connor Hellebuyck attracted media attention.^[26][27] The Golden Knights prevailed in five games.^[20][19] In Game 3 of the team's second-round series against the Edmonton Oilers, Brossoit exited the game after injuring himself in the process of making a save.^[28] Hill took over the net, leading the team onward to the 2023 Stanley Cup Finals.^[29] The Golden Knights defeated the Florida Panthers in five games, and Brossoit joined the team in hoisting the Stanley Cup.^[30]

Return to Winnipeg (2023–present)

On July 1, 2023, Brossoit signed a one-year, $1.75M contract with the Jets to return to Winnipeg.^[31] The 2023–24 season proved a great success for the Jets, who finished fourth in the league, while Brossoit called it "a blessing to be here" while seeking to reestablish his ability to play and remain healthy after previous injuries. He was the Jets' nominee for the Bill Masterton Memorial Trophy, awarded by the Professional Hockey Writers' Association to the player who "exemplifies the qualities of perseverance, sportsmanship and dedication to the game."^[32] The Jets allowed a league-low 199 goals over 82 games, earning the William M. Jennings Trophy as a result, but Brossoit was not eligible to have his name on the trophy as he had played only 23 games, two short of the minimum to qualify.^[33]