The sister of the artist, Letitia Marion Hamilton, Eva Henrietta Hamilton was born in Dunboyne in Ireland. With her sister, she studied at the Metropolitan School of Art in Dublin, under William Orpen and then under Henry Tonks at the Slade School of Fine Art. She began exhibiting with the Water Colour Society of Ireland in 1898.
Hamilton specialised in portrait painting, examples of which include her painting of the dramatist, Lady Augusta Gregory. Between 1904 and 1945 she showed around 120 works at the Royal Hibernian Academy. She also exhibited at the 1907 Irish International Exhibition, the Fine Art Society and the Goupil and Walker Art Galleries.