[12] Chapin attended St. Paul's School in Concord, New Hampshire,[13] and graduated from Harvard College, where he received a bachelor's degree in history, in 1950.

[14] Chapin served as the Chargé d'affaires ad interim in Chad for four month following the establishment of the Embassy in Fort Lamy (now N'Djamena) on February 1, 1961.

Chapin then worked for the Agency for International Development, a Foreign Service examiner, was head of the country desk for Bolivia and Chile, and from 1970 to 1972, he was consul general in Sao Paulo, Brazil.

[19][20] Following his service in Ethiopia, he was a Deputy Assistant Secretary of Defense, charged with international security affairs in Latin America.

Ambassador to Guatemala,[22] to succeed Frank V. Ortiz, Jr.[23] He presented his credentials on September 3, 1981, and served until February 28, 1984, when he left his post.

[26] Cornelia, an alumnus of Miss Fine’s School in Princeton and a Vassar College graduate, was the daughter of Dr. and Mrs. Francis Mann Clarke.