Percy Galbraith began to show immense natural hockey talent at a very young age. In fact he was playing in the Manitoba Senior Hockey League by the time he was just 16. Beginning in the fall of 1917 he missed two years of playing time while serving Canada in World War One. When he returned for the 1919-20 season at the age of 21, he played for a year with the Winnipeg Monarchs.
In 1920-21 Galbraith began a five-year playing career with Eveleth of the USAHA before joining the Boston Bruins of the NHL in 1926-27. In his rookie year Galbraith was a pleasant surprise, contributing nine goals and 17 points while playing in all 42 games. He played in a Bruins' uniform for seven years, managing to avoid any lengthy injuries throughout his tenure.
In 1933 Galbraith was traded to Ottawa, but after just two games with the Senators he was released. There had been rumors that Galbraith purposely got himself released from the team. Whether true or not, he got his wish and was quickly re-signed by the Bruins where he played his final NHL season in 1933-34. In 347 NHL games, Galbraith notched 29 goals and 60 points. He continued to play competitive hockey for another five years before coaching the St. Paul Saints of the AHA in 1939-40.