Which african american pressured fdr to issue an executive order to make discrimination in military hiring illegal?

The correct answer is Asa Philip Randolph

He was a political activist that fought for civil rights and was one of the most important people that influenced the creation of the Executive Order 8802 which was the one mentioned in the question. He was also instrumental in the issuing of Executive Order 9981 during Truman which ended racial segregation in the military.