From late 1975 to the end of his tenure, Bishop O'Leary had the valuable assistance of Auxiliary Bishop Amedee Proulx. This assistance continued on with Bishop Joseph Gerry until Bishop Proulx's death in 1993.

On November 12, 1975, the first Franco-American and youngest to be named to the Episcopacy for the Diocese of Portland, Amedee Proulx was consecrated Auxiliary Bishop.

He was born August 31, 1932, in Sanford, Maine, the son of Francis A. and Rose Seigny Proulx, and one of seven children. The family attended Holy Family Church in Sanford, where he was an altar boy. He attended Holy Family Parochial School. He later prepared for the priesthood at St. Hyacinth Seminary in Quebec, and St. Paul's Seminary, Ottawa, Canada.

On May 31,1958, Amedee Proulx was ordained a priest at the Cathedral of the Immaculate Conception in Portland by Bishop Daniel J. Feeney. Following his ordination, he served in parishes in Portland, Caribou, Fort Kent and Auburn. He was especially effective in the French communities because of his facility in the language, which Bishop O'Leary had stated would be a valuable asset, when together they visited those Franco areas.

On October 2, 1966, Father Proulx was sent to Catholic University in Washington, D.C., to study Canon Law and received his Licentiate in Canon Law.

He returned to the Diocese of Portland and was appointed Secretary to the Tribunal on June 21, 1968 and Assistant Vicar for Religious on September 25, 1968. In 1970, Bishop Peter Gerety appointed him Vicar for Religious. In 1971, he was promoted to Prelate of Honor to His Holiness, Pope Paul VI, and in 1975 Bishop O'Leary reappointed the then Msgr. Proulx, Episcopal Vicar for Religious. On November 12, 1975, he was consecrated Auxiliary Bishop.

During the years that Bishop Proulx served as Auxiliary Bishop, he was instrumental in responding to the concerns of the religious communities and to women Catholics in general throughout the state. In 1992, although already ill, he was one of the framers of the United States Bishops' "Pastoral Response to the Concerns of Women in the Church and Society." He also instituted a successful program for the rehabilitation of diocesan priests suffering from alcoholism. Bishop Proulx was esteemed for his wisdom and compassion, and upon his death on November 22, 1993, both of these groups and the diocese itself lost a kindly and forceful advocate.

Bishop Proulx is buried in Calvary Cemetery.