He dropped out to serve in the Coast Guard before returning to earn a Bachelor of Arts in economics.
[4] He worked at the personal injury firm of Badger, Parrish before joining the Small Business Administration.
[5] In 1963, Markham was appointed by President John F. Kennedy to serve as an Assistant United States Attorney for the District of Massachusetts.
He remained a U.S. Attorney until 1969 when he resigned to work in private practice, with the Boston firm of Moulton, Looney, Mazzone, Falk, & Markham.
[5] Markham was present on Chappaquiddick Island, Massachusetts, on the night leading up to the death of Mary Jo Kopechne.
According to the testimony of Senator Edward M. Kennedy, after the accident, he, Markham, and Joseph Gargan returned to the waterway to try to rescue Kopechne.