Marie Curtis Park is situated on both banks of the Etobicoke Creek where it flows into Lake Ontario. Native people frequently visited the area and named the creek Etobicoke for "place where the wild alders grow". Augustus Jones, a crown-appointed surveyor, Anglicized the name to Black Alders Creek around 1800.

The park was created in 1954 after the high flood waters caused by Hurricane Hazel devastated a number of low-lying properties. The disaster prompted provincial and municipal governments to administer flood protection. Due to their hazardous location on the flood plain, 164 homes were acquired and removed.

Public parkland was purchased by the former Village of Long Branch, the former Municipality of Metropolitan Toronto, and the Province of Ontario. An additional gift of the Canadian Arsenals property by the Government of Canada, and some municipal land held by the Village of Long Branch, created a sizable parkland area. In 1958, two private donations occurred: playground facilities by the Canadian Progress Club (Lakeshore Branch) and a drinking fountain by the Lakeshore Business and Professional Women's Club. In 1982, the 15.7 hectare Canada Post property, flanking the parks' western edge, was acquired by the former Metropolitan Toronto and Region Conservation Authority to be integrated with Marie Curtis Park.

Marie Curtis was first elected as Reeve of the Village of Long Branch in 1953, a position she held until 1962. She was a member of the first Metro Council which began January 12, 1954, and later played an instrumental role in the formation of a regional parkland system in Toronto. In recognition of her outstanding contributions the park was named in her honour on June 5, 1959.