Born in Greensboro, Alabama, Selden attended the public schools. He graduated from Greensboro High School in 1938 and from the University of the South, Sewanee, Tennessee, in 1942. He served in the United States Navy from August 1942 until March 1946, with 31 months aboard ship, primarily in the North Atlantic, and was discharged as a lieutenant. He served as lieutenant commander in the United States Naval Reserve. He entered the University of Alabama School of Law and graduated in 1948. He was admitted to the bar in 1948 and commenced practice in Greensboro, Alabama. He served as member of the State house of representatives in 1951 and 1952.
Selden was elected as a Democrat to the Eighty-third Congress. He was reelected to the seven succeeding Congresses (January 3, 1953-January 3, 1969). He was not a candidate in 1968 for reelection to the United States House of Representatives but was an unsuccessful candidate for nomination to the United States Senate. He resumed the practice of law until October 1970. Principal Deputy Assistant Secretary of Defense (International Security Affairs), October 1970-February 1973. Ambassador to New Zealand, Fiji, The Kingdom of Tonga, and Western Samoa from 1974 to 1979. He was an unsuccessful Republican candidate for nomination to the United States Senate from Alabama in 1980. He served as president, American League for Exports and Security Assistance from 1980 to 1985. He was a resident of Greensboro, Alabama, and Falls Church, Virginia, until his death in Birmingham, Alabama, November 14, 1985. He was interred in Greensboro City Cemetery, Greensboro, Alabama.