Clark counted among his supporters, his teachers Frank Copeland and Earl Horter who helped to foster his artistic growth. As a young enterprising college student, Clark’s exposure to Van Gogh’s way of handing paint had an indelible impact on his own personal technique. Clark soon developed an affinity using a palette knife to work his richly endowed canvases with billowing, curvature lines and figurative imagery. He was introduced to the abstractionism of the 1930’s, however, the bulk of Clark’s work remained largely representative in nature.

He struggled, as did many artists of the day, during the Great Depression to find work. From 1932-1942, Clark worked for the Works Progress Administration (WPA). Despite the economic challenges of the time, Clark remained a prolific artist. Some of his most sought after images include those bearing the influences of Social Realism. Similar to his friend Elizabeth Catlett, who aligned herself with the ideologies of Mexican muralists such as Diego Rivera, Clark felt that art should benefit and speak to the common community.

Also, like Catlett, Clark joined a graphic arts shop where he was affiliated with artists that were noted for their activism. Clark is described as having charted “the emotional and economic crossroads experienced by black society” during very tumultuous times in the black community. His activism took place when transformational events—desegregation, economic disenfranchisement, and racist attacks on Black communities and institutions was at its height in the United States. However, despite the pressures of this time Clark’s first solo show, "The Negro Comes of Age" opened at the Artist's Gallery of Philip Ragan Association in Philadelphia, Pennsylvania in 1940.

Clark was as devoted to educating and mentoring young people as he was to his own professional advancement. He established a full-time art department at Talladega College in Alabama before moving to California. In the final years of his career, Clark worked at Oakland's Merritt College where he remained until his retirement in 1981.