Despite these challenges, Davis worked within the army's white hierarchy to attain a record of superior technical and tactical proficiency as he slowly rose through the ranks.

Though he was near retirement, political considerations during the 1940 United States presidential election, the need to obtain the support of black citizens for U.S. involvement in World War II and Davis's own long record of accomplishments led to his promotion to brigadier general.

He attained the mandatory retirement age of 64 in 1941, but remained on active duty to perform wartime inspections of black units and offer observations and recommendations on policies including racial integration.

[10] He also participated in the cadet program, in which city high schools organized military units that competed against each other in marksmanship, drill and ceremony, and other soldier skills.

[21] Palmer and Davis quickly recruited their company, and on July 13, 1898, Davis was commissioned as a first lieutenant in the 8th U.S. Volunteer Infantry's Company G.[22] He was soon appointed as his battalion's adjutant, in addition to duty as officer in charge of prisoners awaiting court-martial, and was stationed at Fort Thomas, Kentucky, and Chickamauga Park, Georgia, from October 1898 until the regiment was disbanded in March 1899.

[23][24] In late 1900, Davis's unit was commanded by Lieutenant Charles Young, one of a handful of African American officers serving in the U.S. military at that time.

[31] While Davis was not known for developing personal or emotional bonds with his soldiers, they still regarded him highly, with most describing him as stern with respect to military discipline, but well liked.

[36] In September 1905, Davis was assigned as professor of military science and tactics at Wilberforce College, a traditionally black institution of higher learning.

[37] Davis's additional duties while at Wilberforce including serving as the regular army inspector and evaluator of training for the District of Columbia National Guard's 1st Separate Battalion.

[38] As a result, his assignment at Wilberforce and his additional duty with the 1st Separate Battalion were extended for a year after he had completed the usual three-year tour in 1908.

[45] In early 1917, Davis requested reassignment to a troop unit, arguing that the circumstances at the college, chiefly friction between its president and him over issues including student discipline, left him unable to perform his duties effectively.

[55] During the summer months of 1930 to 1933, Davis escorted pilgrimages of black World War I Gold Star mothers and widows to the burial places of their loved ones in Europe.

[57] Davis served in this assignment only briefly, because in May, Governor Herbert H. Lehman commissioned him as a colonel in the National Guard and appointed him to command the regiment.

[62] Army leaders did not include Davis on a list of colonels slated for promotion in late 1940, claiming that he was too close to the mandatory retirement age of 64.

[66] Davis oversaw the brigade's preparations for entry into the war, including individual and collective training, and non-commissioned and commissioned officer selection and education.

[67] He also served as acting division commander during the absence of his superior, Major General Terry de la Mesa Allen Sr.[67] When Davis departed this assignment several months later, Allen attested to Davis's superior leadership when he reported to the War Department that 4th Brigade had made a slow start in getting organized and trained, but was finishing strong and would soon be prepared for combat.

[67] In June 1941, General George C. Marshall, the army's chief of staff, inquired whether Davis was willing to continue serving beyond his mandatory retirement date in July.

[68] Marshall's plan was for Davis to serve as an assistant to the army's inspector general, with specific responsibility for identifying and resolving concerns arising from the expanded use of segregated black units.

[71] On November 10, 1944, Davis was reassigned as special assistant to Lieutenant General John C. H. Lee, commander of Communications Zone, European Theater of Operations.

[72] After serving in the European Theater of Operations for more than a year, in November 1945 Davis returned to Washington, D.C.[73] In February 1946, he was assigned as assistant to the army's inspector general.

[75] In this posting, he was responsible for policy review and recommendations with respect to the role of African Americans in the army, including plans for desegregation.

[76] On July 26, 1948, President Truman issued Executive Order 9981 which abolished racial discrimination in the United States armed forces.

[78][79] As a member of the commission, he made numerous trips around the United States and to Europe to commemorate veterans and dedicate monuments and memorials.

[82] Some historians, including Russell Weigley, regard Davis as a significant figure not for his personal accomplishments, since the army often relegated him to assignments considered less than prestigious, but because his prominence represented an indicator of forward movement for African Americans with respect to equality and desegregation.

[83] Historian Jeffrey L. Jones assessed Davis's legacy with respect to race relations as an individual willing to accept a behind the scenes role that enabled him to indirectly advocate for greater equality in the military and society as a whole.

[84] Many of the changes Davis advocated during World War II were considered only temporary by army leaders, but were eventually codified after President Truman moved to desegregate the military.

[87] The District of Columbia home in which Davis lived during his retirement, 1721 S Street NW, is part of Cultural Tourism DC's African American Heritage Trail.

[90] The hall was created in 1969 and recognizes outstanding soldiers who were stationed at Fort Leavenworth and contributed significantly to the army's history, heritage and traditions.

[93] The plaque's front and back detail several of his accomplishments, including his service at Wilberforce, regimental command, and promotion to brigadier general.

[93] Benjamin O. Davis Veterans of Foreign Wars Post 311 in Richton Park, Illinois, is named for both the senior and junior Davises.