In 1915, he joined the Seattle Metropolitans, where he stayed for nine seasons, contributed to another Stanley Cup win, and twice topped the league in goal scoring. His third try for the Stanley Cup ended in a tie when the fifth and final game of the series was cancelled due to the influenza epidemic in 1919, the only year in which the Stanley Cup was not awarded. His last Stanley Cup win came in 1925 with the Victoria Cougars. As testimony to his athletic talent and versatility, Foyston was selected in various years to play on the PCHA’s All-Star Team at three different positions—center, rover, and left wing—and was one of the first players to score over 200 career goals.
After retiring as a player in 1929, Foyston stayed on with his CPHL team, the Detroit Olympics, as a coach. He later coached an NWHL team, the Seattle Seahawks, from 1933 to 1937. Foyston, who was a star attraction wherever he played, was elected to the Hockey Hall of Fame in 1958.