Mina Loy was born Mina Gertrude Löwry in London, England. Her mother Julia Bryan was English, and her father Sigmund Löwry was a Hungarian. Upon leaving school at age seventeen, she moved to Munich and studied painting for two years. When she returned to London, she continued to study painting, once having Augustus John as a teacher. During her studies, she became familiar with the latest advanced theories in Europe, such as that of Nietzsche, Bergson, Freud, as well as teachings of the East. She moved to Paris, France with Stephen Haweis who studied with her at the Académie Colarossi. The couple married in 1903. Loy is first cited using her new last name in 1904, when she exhibited six watercolor paintings at the Salon d'Automne in Paris. Loy and Haweis had their first child, Oda, in 1904. Oda died on her first birthday.

Loy soon became a regular in the artistic community at Gertrude & Leo Stein's salon, where she met many of the leading avant-garde artists and writers of the day. Loy would meet the likes of Guillaume Apollinaire, Pablo Picasso, and Henri Rouseau. During her three years in Paris, she, Gertrude Stein, and Djuna Barnes would develop lifelong friendships.

In 1907, Loy and Haweis moved to Florence, Italy where they lived more or less separate lives, becoming estranged. Despite drifting apart, they had two more children: Joella in 1907 and Giles in 1909. It was during this time that Loy became part of the Futurists community, having a sexual relationship with their leader Filippo Marinetti. While attending gatherings held at Mabel Dodge's Medici villa, she also networked with expatriates from Manhattan. Among this group were journalist and communist John Reed, as well as novelist and critic Carl Van Vechten. Vechten would eventually become Loy's agent. In early World War I, Loy would serve in an army hospital.

Loy's extremely original poems started to frequent smaller magazines such as Rogue, attracting the attention of the New York avant-garde. Once her work started to gain momentum, she began to publish poems and articles in more significant New York publications. In 1914, "Aphorisms on Futurism" was published in Alfred Stieglitz's Camera Work. "Parturition", her graphic depiction of childbirth, was printed in Trend.

In July 1915, Loy began to write what would be later known as "Songs to Joannes" "(originally "Love songs"), a collection of modernist, avant-garde love poetry about her disenchantment with Giovanni Papini, another founding Futurist with whom Loy had been in a romantic relationship with in Florence. First readers of "Songs to Joannes" were shocked by Loy's forward expressions of human sexuality, particularly the grotesque and uncensored depictions of erotic desire and bodily functions. However, beyond the surface, Loy exposed the inequities and hypocrisies of male dominated society, and the resulting damage suffered by women physically and emotionally. She also unleashed criticism against supposedly superior theories held by fellows artists.

Disillusioned with the macho elements in Futurism and its move towards Fascism, as well as desiring a divorce from her husband Stephen Haweis, Loy left her children with a nurse and moved to New York in 1916, where she began acting with the Provincetown Players. She was a key figure in the group that formed around Others magazine, which also included Man Ray, William Carlos Williams, Marcel Duchamp, and Marianne Moore. She also became a Christian Scientist during this time. Loy soon became a leading member of the Greenwich Village bohemian circuit. She also met the 'poet-boxer' Arthur Cravan, self-styled Dadaist and fugitive from conscription. Cravan fled to Mexico to avoid the draft; when Loy's divorce was final she followed him, and they married in Mexico City. Here, they lived in poverty, and years later, Loy would write of their destitution.

Once Loy became pregnant, the couple realized they needed to leave Mexico. A few months later, Cravan set sail for Buenos Aires in a small yacht as Loy watched from the beach. He sailed over the horizon, disappeared without a trace, never to be seen again. The tale of his disappearance is strongly anecdotal, as recounted by Loy's biographer, Carolyn Burke. Their daughter was born April 1919.

Loy would return to Florence and her other children. However, in 1920 she would set out for New York, hoping to find Cravan, unable to accept his death. Here she returned to her old Greenwich Village life, perusing theater or mixing with her fellow writers. She would mingle and develop friendships with the likes of Ezra Pound, Dadaist Tristan Tzara, and Jane Heap. In 1923, she returned to Paris and, with the backing of Peggy Guggenheim, started a business designing and making lampshades, glass novelties, paper cut-outs and painted flower arrangements. Her first book, Lunar Baedecker was also published that year. She picked up old friendships with Djuna Barnes and Gertrude Stein. She would continue to write and grow close with Hilda Doolittle a.k.a H.D and her lover Winifred Ellerman (otherwise known as Bryher).

In 1936, Loy returned to New York and lived for a time with her daughter and her lesbian lover in Manhattan[citation needed]. She moved to the Bowery, where she became interested in the Bowery bums, writing poems and creating found art collages on them. In 1946, she became a naturalized citizen of the United States. Her second and last book, Lunar Baedeker & Time Tables appeared in 1958. She exhibited her found art constructions in New York in 1951 and at the Bodley Gallery in 1959. In 1953, Loy moved to Aspen, Colorado, where her daughters Joella and Fabienne were already living; Joella had married the Bauhaus artist and typographer Herbert Bayer. In Colorado, she continued to write and work on her junk collages up to her death at the age of 83, in Aspen, Colorado.

Loy also wrote a novel, Insel, which was published posthumously.