Mary Helen McKean Malcolmson was born in Ireland in 1864. She immigrated to Ontario with her family where they settled in Almonte. Her father ran a furniture factory.

Eventually Mary resided in St. Catharines where she became highly involved in community endeavors: she was instrumental in founding the St. Catharines branch of the Women’s Canadian Club, the Victorian Order of Nurses and the St. Catharines Council of Women. She was also a well-known officer of the I.O.D.E. (Imperial Order Daughters of the Empire) and convener in the National Council of Women of Canada. She also took a great interest in the welfare of youth. She worked closely with the Girl Guides to bring a branch of the troop to St. Catharines. It was because of her efforts that the first Girl Guide troop in Canada was formed in St. Catharines in 1910. She was honoured for her work with the Girl Guides with a Silver Jubilee Medal in 1935.

Mary Malcolmson died in St. Catharines on July 7th, 1935 and was buried at Victoria Lawn Cemetery.