She was second in command of Smith College's art department from 1888 to 1906 under Dwight William Tryon and earned acclaim for paintings of her native New England and scenes from her wide travels in Europe, from Norway to the Paestum ruins south of Naples.
Mary and her surviving sisters Lucy, Abby and Laura were all star students at Hartford Public High School, and none ever married.
Although she was Episcopalian, she attended Catholic church services in Europe (sometimes numerous times in a row on Sundays) and wrote lavish descriptions of the costumes and music to her sisters.
She lived in Paris in 1898–99 (she studied then at the Ecole des Beaux-Arts and with James Abbott McNeill Whistler) and 1906–07, in flats on rue Boissonade, with numerous other painters nearby.
Virtually all biographical information for Mary Rogers Williams (1857–1907) comes from her archive in a private New England collection, a promised gift to Smith College, which contains diary entries, sketches, letters and clippings and other ephemera including concert programs and confetti from Paris parades.
She wrote home from her frequent trips in Europe almost every day, delving into topics including her works in progress, passing scenery, treatment of women travelers, and her criticisms of ancient building restorations and of art and recent art restorations in European museums and gallery shows.