In 1933 he finished DePauw University in Greencastle, Indiana, United States and attained Bachelor of Arts degree.
Coffin began his career at the Indianapolis Times as a reporter in 1933, only to leave the field briefly in 1937 when he became Governor Clifford Townsend’s press secretary. In 1941 Coffin became the assistant to the director of the Office of War Information. From 1945 till 1947 Coffin worked as a correspondent of Columbia Broadcasting System. From 1948 till 1951 he was a newspaper columnist.
Beginning from 1951 till 1968 Tristram Coffin worked as a freelance writer and broadcaster.
In 1968 Coffin began the Washington Watch newsletter, which later became the Washington Spectator. To produce his newsletter, which had a circulation of about sixty-five thousand, he used a typewriter until he passed over the editorship in 1993.
On June 26, 1933 he married Margaret Avery. The couple had two children - Lynne, Stephen Avery.