Alberta native Brock Gallagher played in Major League Rugby between 2024-2025. He represented the Dallas Jackals (2024) and the Seattle Seawolves (2025).

Prior to his entry into MLR, Gallagher had represented Canada at U18, U19, and U20 levels, and has played with the Loggerheads in Premier Rugby Sevens between 2022-2023, winning the men’s title both years. He also played with the Cape Town Wild Dogs in the Rugby Tens Series.

On 26th October 2023, the Dallas Jackals announced the signing of Gallagher for the 2024 MLR season. He earned 15 appearances for the Jackals during their remarkable 2024 season, scoring 1 try and helping them qualify for the playoffs for the first time in team history. He came of the bench during their nailbiting Western Conference Final defeat to the Seattle Seawolves. Following the 2024 season, the Dallas Jackals and MLR announced that the team would not participate in the 2025 season. In the subsequent dispersal draft, Gallagher was selected 21st by the Seattle Seawolves, who confirmed his signing on December 4th, 2024.

Prior to his appearance for the Jackals in the 2024 playoffs, Brock Gallagher earned his test debut for Canada when he came off the bench against Scotland in the July tests. He earned his first start for Canada against Romania in the 2024 November tests.