Reuben Kadish was born in Chicago on January 29, 1913. His father and mother were from Latvia and the Ukraine respectively.
In 1921, the family moved to East Los Angeles, California, where Kadish studied painting under Lorser Feitelson. During this time, he befriended Jackson Pollock and Philip Guston, who attended the Manual Arts High School.
During a trip to New York City in 1930, Kadish was impressed with the modern art, especially the work of the Surrealists, which he saw there. Upon his return to Los Angeles the following year, Kadish attended the Otis Art School, the Stickney School of Art in Pasadena, and Los Angeles City College. He also shared a studio with Philip Guston.
In 1933, Kadish, Guston and Jules Langsner were apprenticed to Mexican muralist, David Alfaro Siqueiros. Their most notable work being the mural "Triumph of Good Over Evil", at the University of Morelia in Mexico. During the next three years, the three young artists collaborated on painting murals in California and Mexico. After another visit to New York, Kadish was invited to San Francisco by Bill Gaskin to head the art division of the WPA project there, a position he occupied until 1940.
From 1940, Kadish worked as a coppersmith and welder at the Bethlehem Steel Works in San Francisco until 1942, when he joined the Army as a member of the War Artist Unit, serving in India and Southeast Asia during World War II. In 1944, he rejoined his wife Barbara in the Bay Area, but they soon returned to New York City, where Kadish worked for Stanley William Hayter at Atelier 17. In the summer of 1945, the Kadish painted with Jackson Pollock and Lee Krasner in a shared Long Island house on Slow's Point in Amagansett.
In 1946, the Kadishes moved to a dairy farm in Vernon, New Jersey, where they supported themselves by farming until 1957. A catastrophic fire in the studio destroyed most of Kadish's paintings in 1947, causing him to turn his interest to creating sculpture.
After teaching art and design at the Newark School of Fine and Industrial Art in 1957, Kadish taught sculpture at the Brooklyn Museum Art School from 1958-1959. In 1960, he began his thirty-year teaching career at Cooper Union, which ended only a few months before his death on September 20, 1992 in Manhattan.