As an adolescent he became acquainted with Robert Church Jr., the president of Solvent Savings Bank and Trust and a member of the national board of the NAACP, who was mentoring his friend Lonnie Brisco.

[5][a] Cumby alleged that the pre-repatriation indoctrination of American POWs was intended to create a nucleus of post-war civilians who would advocate in the United States for these objectives.

[1] Cumby retired from the U.S. Army in 1961 at the rank of lieutenant colonel and entered the United States Foreign Service, holding overseas postings in Thailand and Spain.

According to Cumby, upon accepting the assignment, she "knew practically nothing of the separate schools for Negroes" and had volunteered "not because of any great race consciousness ... but because the pay scale was more attractive".

[14] A resident of Silver Spring, Maryland, in 1976 he campaigned for the reelection of United States Senator John Glenn Beall Jr.[15] He died of cancer at Walter Reed Army Medical Center at age 69.