 As an economist, Harris is most famous for his 1931 collaboration with political scientist Sterling Spero to produce a study on African-American labor history titled "The Black Worker" and his 1936 work "The Negro as Capitalist", in which he criticized black businessmen for not promoting interracial trade.He headed the economics department at Howard University from 1936 to 1945 and taught at the University of Chicago from then until his death.As a social critic, Harris took an active radical stance on racial relations by examining historical black involvement in the workplace, and suggested that African Americans needed to take more action in race relations.