In 1942, Robinson was drafted and assigned to a segregated Army cavalry unit in Fort Riley, Kansas. Having the requisite qualifications, Robinson and several other black soldiers applied for admission to an Officer Candidate School (OCS) then located at Fort Riley. Although the Army's initial July 1941 guidelines for OCS had been drafted as race neutral, few black applicants were admitted into OCS until after subsequent directives by Army leadership. As a result, the applications of Robinson and his colleagues were delayed for several months. After protests by heavyweight boxing champion Joe Louis (then stationed at Fort Riley) and with the help of Truman Gibson (then an assistant civilian aide to the Secretary of War), the men were accepted into OCS. The experience led to a personal friendship between Robinson and Louis. Upon finishing OCS, Robinson was commissioned as a second lieutenant in January 1943. Shortly afterward, Robinson and Isum were formally engaged.