Loy was born Mina Gertrude Lowy in London, England. On leaving school, she studied painting, first in Munich for two years and then in London, where one of her teachers was Augustus John. She moved to Paris, France with Stephen Haweis who studied with her at the Académie Colarossi. The couple married in 1903. She first used the name Loy in 1904, when she exhibited six watercolor paintings at the Salon d'Automne in Paris.
Loy soon became a regular in the artistic community at Gertrude Stein's salon, where she met many of the leading avant garde artists and writers of the day. She and Stein were to remain lifelong friends.
In 1907, Loy and Haweis moved to Florence, Italy where they lived more or less separate lives, becoming estranged. Loy mixed with the expatriate community and the Futurists, having a sexual relationship with their leader Filippo Marinetti. At this time, she began what would be later known as "Songs to Joannes" [1]", a tour de force of modernist, avant-garde love poetry about Giovanni Papini, another Futurist with whom Loy had an unsuccessful relationship in Florence. She also started to publish her poems in New York magazines, such as Camera Work, Trend, and Rogue. She was a key figure in the group that formed around Others magazine, which also included Man Ray, William Carlos Williams and Marianne Moore. She also became a Christian Scientist during this time.