[2] He was in the United States Army in the aftermath of World War II, from 1945 to 1947.

[3][4] He was in private practice in Washington, D.C. from 1953 to 1970, when he became a judge on the Superior Court of the District of Columbia from 1970 to 1972.

He then served on the District of Columbia Court of Appeals from 1972 to 1982.

[5] In 1980, Harris was one of several more conservative judges, led by Frank Q. Nebeker, who attempted unsuccessfully to prevent the reappointment as chief judge of Theodore R. Newman Jr.[6] He left the court to become the United States Attorney for the District of Columbia from February 5, 1982, to 1983, where he helped prosecute John Hinckley Jr.[7][4] On November 1, 1983, Harris was nominated by President Ronald Reagan to a seat on the United States District Court for the District of Columbia vacated by Judge John Lewis Smith Jr.[7] Harris was confirmed by the United States Senate on November 11, 1983, and received his commission on November 14, 1983.

He assumed senior status on February 1, 1996, and served in that capacity until June 2, 2001, when he retired.