Marymount School was founded in 1926 as one of a worldwide network of schools directed by the Religious of the Sacred Heart of Mary, an international order of women established in 1849 in Béziers, France. Members of the community came to the United States in 1877 and established their first ministry in Sag Harbor, NY. In 1903, Mother Joseph Butler, RSHM, was assigned to the United States. Her farsighted vision of the role education must assume for women led her to found the first Marymount school in Tarrytown, NY. In response to the need for strong, Catholic independent education in New York City, Mother Butler purchased the Florence Vanderbilt estate at 1028 Fifth Avenue in 1926 and founded Marymount School of New York, a school dedicated to educating the whole person and preparing young women for significant roles in the world.
The School flourished, and in 1936 the adjoining Pratt mansion at 1027 Fifth Avenue was acquired. In 1950, the School purchased the Dunlevy Milbank property at 1026. The three turn-of-the-century Beaux-Arts buildings occupy approximately half the block between 83rd and 84th Streets on Fifth Avenue. Today the Board, with twenty-nine members, is composed of current parents, past parents, alumnae, friends, and three members of the Religious of the Sacred Heart of Mary.
In the past two decades, the School has experienced extensive expansion in size and in program. A gymnasium was built on the roof of the three buildings in 1984, launching the School into strong interscholastic athletic competition. In 1994, three state-of-the-art science labs were created on the top floors of two of the buildings. In August 1999, Marymount purchased a town house at 2 East 82nd Street to serve as the home of the Middle School. In September 2002, the new site opened and currently houses Classes IV through VII. In the summer of 2003, the Fifth Avenue buildings were renovated to expand science and art facilities and to improve other areas of school life.
For over eight decades, Marymount School has been committed to the founding vision of the Religious of the Sacred Heart of Mary, Mother Butler and the other founding women: to educate girls and young women to their full potential in a challenging, stimulating, and value-centered learning environment.