He was in the United States Army during World War II, from 1941 to 1946, thereafter remaining in the United States Army Reserve until 1966, achieving the rank of colonel in the Judge Advocate General's Corps.

He was special counsel to the State Attorney General of Rhode Island from 1948 to 1952.

He was confirmed by the United States Senate on June 29, 1966, and received his commission the same day.

He served as Chief Judge from 1971 to 1982, assuming senior status on July 6, 1982.

Pettine served in that capacity until his death on November 17, 2003, in Dallas, Texas.