Ruth Salter Wainwright was born in Sydney in 1902. She studied art with Lewis and Edith Smith at the Halifax Ladies College from 1917 to 1921. In 1921 she was certified as an art teacher but it was not until the 1950s that Wainwright started teaching in her studio, a practice she continued for most of her life. She also graduated, in 1924, as a concert harpist from the Halifax Conservatory of Music. From 1930 to 1940 she played with a CBC radio orchestra located in Halifax.
She was first trained in the then dominant English academic tradition of art as practiced and taught by British artists such as Elizabeth Nutt and Stanley Royle, both of whom had moved to the Maritimes. She began to exhibit during the 1940s with the Nova Scotia Society of Artists and the Society of Painters in Watercolour. 1953 was a turning point in her artistic practice. She studied under the American abstract expressionist Hans Hofmann at his school in Provincetown during the summer of 1953 and 1955. This experience allowed her to turn from copying nature to the creation of plastic space, enabling her to find and emphasize tensions within her subject matter. While others were content with the dominant themes of representation in regional art practices, Wainwright developed a style related to American abstract expressionism and became a pioneering Maritime Modernist. Her subjects, executed in styles ranging from naturalism to abstraction, embrace the landscapes of the Maritimes, Newfoundland, England and beyond. As both an artist and a teacher, Wainwright provided support to generations of younger artists in Atlantic Canada.
She exhibited extensively in Nova Scotia and New Brunswick throughout her career, as well as in New York (1962) and London (1964-65). Her work was included in four National Gallery of Canada exhibitions. The Art Gallery of Nova Scotia holds over seventy of her drawings and paintings.