Davis was born in Washington D.C. and, although his army records and gravestone claim that he was born in 1877, his biographer has found a census document that suggests he was actually born three years later and falsified his birth year in order to join the army.
Davis first entered military service following the outbreak of the Spanish-American War in 1898, and later served as Professor of Military Science and Tactics at both Wilberforce University in Ohio and Tuskegee University in Alabama as well as serving tours of duty around the world. Having been assigned to the 369th Regiment, New York National Guard in 1938, he later took command of the unit and was promoted to brigadier general by President Franklin D. Roosevelt on 25 October 1940.
During the Second World War, Davis was an influential member of the Advisory Committee on Negro Troop Policies. Having been tasked with improving race relations and securing the morale of black soldiers in the European theatre, he lobbied to end segregation and introduce full racial integration. Davis was awarded the Distinguished Service Medal (DSM) on 22 February 1945 for his ‘wise advice and counsel’ that ‘brought about a fair and equitable solution to many important problems which have since become the basis of far-reaching War Department policy.’
Benjamin O. Davis Sr. died on 26 November 1970 and was buried in Arlington National Cemetery. His son, Benjamin O. Davis Jr., had already followed in his father’s footsteps by becoming the first African-American general in the United States Air Force.