Born in 1881 in Villanova, Pa., Gallatin was an influential art collector and abstract painter. He was from a distinguished family whose ancestry included Albert Gallatin, Secretary of the Treasury under Thomas Jefferson and founder of New York University. Bolstered by an inheritance from the family banking fortune, A. E. abandoned a law degree for a career in the arts. He left school before taking his bar exam and later said "I don't know why the devil I did it. I think an abstract artist is of more value to the community than a lawyer." Gallatin started working first as a critic and curator before becoming a collector and finally a painter.
Gallatin first began by collecting art and taking trips to Europe. Through his trips he had his finger on the pulse of Cubism, the new emerging style of abstraction. He abandoned his collecting of American impressionist artists, the Ashcan School, and devoted himself to collecting European Abstraction and fostering its growth in America. Discovering his true direction: He acquired two watercolors by Cézanne and a painting by Picasso. Gallatin’s visits to the landmark exhibition of Post-Impressionist painting held at the Metropolitan Museum of Art in 1921, his involvement for a brief time in Katherine Dreier’s Société Anonyme, and his consultations with Alfred Steiglitz of Gallery 291 all helped to spark his conversion to modernist abstraction.
Often accompanied by Morris, Gallatin made frequent trips to Paris, where he visited Picasso, Georges Braque, Henri Matisse, and other avant-garde artists in their studios and purchased works directly from them. Meanwhile he sought a space in New York in which to publicly exhibit his growing collection. In the spring of 1927 he organized a show of art works at the Library of the School of Commerce at NYU. He soon found a more permanent venue; at the age of 46, he opened the Gallery of Living Art in three specially-constructed alcoves in NYU’s Main Building, overlooking Washington Square. At the time of its inauguration, the Gallery of Living Art was the first and only institution in the country that provided continuous public access to the latest international developments in modern art.
Gallatin began to paint in 1936 and the following year joined the American Abstract Artists Group. The wealthy Gallatin cut an unusual figure among the younger, liberal members of this group; however, he shared their enthusiasm for avant-garde styles in art. A perfectionist, Gallatin would sometimes spend years on a painting, endeavoring to achieve the ultimate in spare simplicity, crisp line, and elegant, subtle color. In style, his painting was indebted to synthetic cubism. This technique that appealed to his intellectual nature because of its emphasis on geometric shapes held in balance in the composition. His neighbors and closest friends were the artists George L.K. Morris, his wife Suzy Frelinghuysen Morris, and Charles G. Shaw. Like Gallatin, they were independently wealthy, well-read, and urbane; with him, they were nicknamed the “Park Avenue Cubists.”
In 1942 he put together a show devoted to American women, including Morris's wife, Suzy Frelinghuysen, as well as Alice Trumbull Mason and Esphyr Slobodkina. That same year New York University informed him that he had to close the Museum of Living Art so that the space it occupied could be repurposed as a wartime economy measure. Greatly disappointed, Gallatin accepted an offer from the Philadelphia Museum of Art to provide a home for it. Within a few months 175 works from his collection were moved to Philadelphia and a few were donated to the Berkshire Museum in Pittsfield, Massachusetts, to which Morris and Frelinghuysen were connected. During the remainder of the 1940s, until his death in 1952, he continued to paint, promote, and collect non-objective art.