Born in 1920 in Washington, D.C., Davis's formal instruction in art was limited to the drawing classes he took in high school. From 1939 to 1968, Davis was a writer and journalist, working at newspapers in Washington, Jacksonville, Florida, and in New York. Always fascinated by art, by 1949 Davis had begun to paint seriously. He has said that visiting The Phillips Collection was one of the strongest influences on him: "The small masterpieces of Paul Klee ...made an unforgettable impression on me, and I can remember being equally smitten with the complex color harmonies of Bonnard. When I first began to paint some years later, it was to the Klees at the Phillips that I went for sustenance and inspiration." He became involved in the Washington art scene in 1950 when he met noted Washington artist and curator, Jacob Kainen, who introduced him to the Washington Workshop Center for the Arts and the artists involved with that organization, among them Morris Louis and Kenneth Noland. Davis' first solo exhibitions were held in 1952. In 1969, Davis began teaching art at the Corcoran School of Art and Design, followed by stints at American University, Skidmore College, and the University of Virginia.
Along with Kenneth Noland, Morris Louis, Howard Mehring, and Thomas Downing, Davis was part of the first generation of Washington color school artists. Like the other members of the Washington Color School, Davis considered color a primary element in painting. The genesis of Davis's signature vertical stripe compositions began in 1952 with The Phillips Collection's Black Flowers (1952). Davis's mature style, characterized by vertical stripes in discretely chosen hues placed in an edge-to-edge arrangement developed in 1959 with The Phillips Collection's Red Devil (1959). For his technique, Davis was indebted to both Louis and Noland, both of whom were involved with the New York art world, particularly through the influential critic, Clement Greenberg. They transmitted the excitement and experimental nature of the New York art scene to Washington artists, particularly the new technique that Davis used in Red Devil—staining and soaking unprimed and unsized canvas with acrylic.
Davis attributed his mastery of color to the Paul Klee room at The Phillips Collection for it was there that he was first exposed to modern art. Visiting the collection in the early 40s, before he had begun to paint, Davis believed that "what constituted color in painting came directly from the French-oriented painting that Mr. Phillips seemed to be fond of." Davis remained fervent in his devotion to The Phillips Collection with the belief that the collection played a crucial role in Washington artists' emphasis on color.