She lived most of her life in France, having settled there with her husband, Álvaro Guevara, from whom she was later separated.

During her time in New York she also wrote for Vogue magazine.

She next moved to Paris, France and studied at both the Académie Julian and Académie de la Grande Chaumière under Francis Picabia and Pierre Tal-Coat.

Although earlier connected romantically to Christopher Wood, also sitting for him, she ultimately married Chilean painter Álvaro Guevara in 1929 and spent most of her life in the south of France, in Aix-en-Provence near him, but not with him, their marriage crumbling after the birth of their daughter Alladine Guevara in 1931.

In 1943, Guinness' work was included in Peggy Guggenheim's show Exhibition by 31 Women at the Art of This Century gallery in New York.