Marshall was motivated by his cousin Jimmy Blanton to work as a jazz bassist. During his time at college ( he studied at Lincoln University in Jefferson City ) played Marshall in 1942 briefly in the band of Lionel Hampton. After three years in the U.S. Army, he worked 1946/47, in a trio of Stuff Smith and then returned to St. Louis, where he formed his own formation. In 1948 he went to New York and became a member of the Mercer Ellington band, followed by the game at the Duke Ellington Orchestra from 1948 to 1955, where he replaced Oscar Pettiford. He was also from 1956 to 1963 a sought-after session musician and worked on recordings by Art Blakey, Donald Byrd, Gigi Gryce, Milt Jackson, Hank Jones, Mary Lou Williams and Kenny Clarke and Lem Winchester; after that he worked mainly in theater orchestras on Broadway. Marshall also played occasional solo passages in the Blanton / Pettiford style.
In 1955 he recorded his only album under his own name, Wendell Marshall with the Billy Byer Orchestra (on RCA). In 1968 he moved back to his hometown to work as an insurance broker.