Gignoux was born in Portland, Maine and attended St. George's School in Newport, Rhode Island in 1933.

He was in the United States Army from January 1942 to February 1946 during World War II.

[3] On August 9, 1957, Gignoux was nominated by President Dwight D. Eisenhower to a seat on the United States District Court for the District of Maine vacated by Judge John David Clifford Jr. Gignoux was confirmed by the United States Senate on August 22, 1957, and received his commission on August 26, 1957.

In 1970, following the rejection of Clement Haynsworth and George Harrold Carswell by the Senate, Gignoux was the runner-up to Harry Blackmun in Richard Nixon‘s quest to fill Abe Fortas’ seat on the Supreme Court.

He assumed senior status on June 1, 1983, serving in that capacity until his death on November 4, 1988, in Portland.