Sam Francis was one of the leading American abstract painters and printmakers of the 20th century. Francis left the U.S. Army Air Corps in 1944 due to spinal tuberculosis. Francis took up painting as a hobby during that time. He decided to make this a serious undertaking studying under David Park in 1947 and completed his BA and MA at the University of California. His use of space on the canvas to allow free circulation of strong color and light developed his style by the time his studies had ended. He was greatly influenced by Abstract Expressionism, particularly the works of Clyfford Still and Jackson Pollock.

Francis moved to Paris in 1950 where he met Jean-Paul Riopelle who was to remain an important influence. The study of Monet's Waterlilies had a profound impact on his work.  His artistic development was affected by his exposure to French modern painting and Asian culture, particularly Zen Buddhism. He spent the 1950s in Paris, having his first exhibition there at the Galerie Nina Dausset in 1952. While in Paris he became associated with Tachisme, and had his work championed by art critics Michel Tapié and Claude Duthuit (son-in-law of the painter Henri Matisse). From a very muted palette, he returned to the qualities of light and color, producing such works as Big Red 1953. He continued to develop the use of white space and increased the dimensions of his paintings for greater emphasis. During this period in Europe he executed a number of monumental mural paintings. He later became loosely associated with a second generation of abstract expressionists, including Joan Mitchell and Helen Frankenthaler, who were increasingly interested in the expressive use of color.
Francis returned to California in 1962 and was then influenced by the West Coast School's preoccupation with mysticism and Eastern philosophy. Blue had become a more dominant feature of his work since 1959 inspired by personal suffering and the great joy of becoming a father for the first time in 1961. This led to combinations of hard color and more disciplined structures with centrally placed rectangles during the 1970s. Eventually these more rigid structures gave way to looser configurations sometimes of snake-like forms with web-like patterns.

Francis painted large murals for the Kunsthalle, Basel in 1956-8 and for the Chase Manhattan Bank, New York in 1959. Paintings by Sam Francis can be found in international museum collections including those of The Metropolitan Museum of Art, The Museum of Modern Art, New York, The Kunstmuseum Basel, the Idemitsu Museum of Arts, Tokyo, and the Centre Pompidou-Musee National d'Art Moderne, Paris. During his lifetime the work of Sam Francis was featured in 113 solo exhibitions in museums and galleries. Since his death in 1994 he has been the subject of over 90 solo exhibitions.