A native of the United Kingdom, Billy Brennagh moved to Canada at a young age and took up lacrosse alongside three of his brothers while living in Manitoba. He eventually found a spot on the Shamrock Lacrosse Club and was with them when they won the Manitoba Provincial Championship in 1903. One year later they journeyed to the 1904 St. Louis World’s Fair, where they captured Olympic gold by defeating the St. Louis Amateur Athletic Association’s squad 8-2. A machinist by trade, he later moved to Port Arthur, Ontario and played on the local lacrosse team. He was inducted into the Manitoba Sports Hall of Fame, along with the rest of his gold medal-winning team, in 2004.