Poindexter was the son of tenant farmers in rural Alabama. He attended Lincoln University, PA, graduating in 1924, then went on to Harvard Medical School in 1929 with a PhD in Microbiology. As a noted bacteriologist, Dr. Poindexter became the head of the Medical College at Howard University in 1934.
In 1948, Senior Surgeon Poindexter was appointed director of the Mission to Liberia, whose goal was to help the Liberian government in sanitation planning and the control of infectious diseases. In the 1940s and 1950s Poindexter’s name became virtually synonymous with study of malaria and other tropical diseases. This work made him one of the most influential (and most overlooked) scientists of all time. Dr. Poindexter published his autobiography, My World of Reality, in 1973.
He was a Prince Hall Mason and member of Omega Psi Phi fraternity.