De Ment attended Phillips High School in Birmingham in 1945 and graduated in 1949.

He rose to the rank of major general and was awarded the Air Force Distinguished Service Medal.

He attended the University of Alabama School of Law and received a Juris Doctor in 1958.

He was the United States Attorney for the Middle District of Alabama from 1969 to 1977, returning to private practice in Montgomery until 1992.

[1] On November 14, 1991, De Ment was nominated by President George H. W. Bush to a seat on the United States District Court for the Middle District of Alabama vacated by Judge Truman McGill Hobbs.