Harry Kerr was a staff sergeant with the 48th Highlanders of Canada when he was selected to represent his nation at the 1908 Summer Olympics. There, alongside Charles Crowe, William Eastcott, Dugald McInnes, William Smith, and Bruce Williams, he won a bronze medal in the military rifle team event. Kerr served with the 2nd Battalion (Eastern Ontario Regiment), Canadian Expeditionary Force, during World War I, where he was temporarily promoted to Lieutenant during the conflict and received the Distinguished Conduct Medal. He also served as a musketry instructor with the army and was well-known in international sport shooting circles, particularly for being the only Canadian to have been a member of a Kolapore Cup winning team on two consecutive occasions (1901 and 1902).