Isabel Duncan was a teenager in 1938 when she began her lengthy playing career with Winnipeg Ramblers of the Greater Winnipeg Senior Girls Softball League. Her position was second base, but she also pitched on occasion. In 1940, she was a member of the city and provincial champion Ramblers. In the early 1940s, she also began playing the outfield where she earned all-star honours with the Dan Davidson’s team. Noted for her strong hitting and excellent defence, she played at the senior level until 1953. She then served as secretary-treasurer of the Senior Girls League until 1958. In the spring of 1955, the league was informed that its home at Osborne Stadium was closing. Duncan and others spearheaded a move to Wesley Park. Her commitment to finding a new home for the league included financial support and countless hours of volunteer work.