[5] In 1908, Beckett traveled to Paris with Katharine Rhoades and Malvina Hoffman and studied in France for two years.

[8] A member of Alfred Stieglitz’s artistic circle in New York City, Beckett was known primarily as a portrait painter.

[12] Marion Beckett and her friends Katharine Rhoades and Agnes Ernst Meyer were known as the "Three Graces" of 291,[11][13] an accolade bestowed by Charles Lang Freer.

[11] In January 1917, Beckett presented a show of portraits at Marius de Zayas's Modern Gallery.

Fifteen of her paintings were stored by family members until 1997, including the portraits of O'Keeffe and Agnes Meyers.

[16] Beckett often traveled to Voulangis, France with Agnes Meyer and Katharine Rhoades to visit artist Edward Steichen and his wife and paint portraits.

[23] In 1917, she worked as a canteen worker for the Red Cross in France,[16][24] and it was during this time period that she is believed to have begun an affair with Steichen.