—At the memorial Mass for Bill Corrigan the Gospel was the Beatitudes. For those who knew him, his life had already been a vivid witness to this Scripture.

Unbowed by age, Mr. Corrigan remained a stalwart Christian activist for peace and social justice, until illness incapacitated him. He died Feb. 25 at the age of 84 of congestive heart failure at Tranquility Hospice in Austell. His body was donated to Emory University School of Medicine.

A memorial Mass was celebrated at Transfiguration Church in Marietta on Feb. 28. Msgr. Patrick Bishop, pastor and friend of the family, was the principal celebrant and Father Roy Bourgeois, founder of School of the Americas Watch, concelebrated the Mass.

Mr. Corrigan’s wife of 59 years, Lillian, has journeyed with him in their active Catholic faith. It has taken them at times to Central America or Washington, but most often to their own community in Marietta or Atlanta, seeking ways to express their commitment to peace and to social justice for the poor.

Parishioners at Transfiguration Church, they have been an active part of the church in Cobb County and of interfaith groups for decades and helped to found Pax Christi chapters in the archdiocese. They belonged to the Cobb Interfaith Peace Studies group, and Mrs. Corrigan started “PJs for peace and justice,” a group sewing pajamas for children in Central America as an expression of solidarity and compassion.

His faith journey took Mr. Corrigan to federal prison at the age of 75 after he participated in a reenactment in 1995 outside Fort Benning, Ga., of the murder in El Salvador of eight Jesuit priests and their housekeeper and her daughter.

The retired Lockheed-Martin engineer took the role of one of the priests in the reenactment. He was sentenced to 60 days in Atlanta federal prison camp for the protest against the School of the Americas located at the base. Nineteen of 26 Salvadoran officers tried for the massacre were trained at the School of the Americas.

He said when he was given his sentence that it was his responsibility to his children and grandchildren “to take a stand against oppression.”

Drawing attention to the School of the Americas “isn’t something you publicize by selling Girl Scout cookies,” Mr. Corrigan said in a prison interview with The Georgia Bulletin.

While he was in prison, Washington Post columnist Mary McGrory learned from Father Bourgeois that Mr. Corrigan was being denied phone privileges to call his wife and made to pick up cigarette butts on the grounds. Writing a July 4 column about this treatment, which led to an immediate improvement for Mr. Corrigan, was one of the best things she’d done in a career in journalism she told students in 2002.

The Corrigans’ concern for the plight of Salvadorans intensified after they visited the Central American country, and Honduras and Nicaragua, in the 1980s. In a church in El Salvador, a sobbing woman spoke to them in Spanish.

“Her five sons had all been killed by the military. The pastor of the church had also been killed. She asked us to be ambassadors for peace,” Mr. Corrigan recalled in 1996. “The Jesuits, Archbishop Oscar Romero, her pastor—all dead. You had to try and find an answer to ‘Why is America backing these people?’”

By nature he tried to respond to injustice with personal action, not pointing a finger at others.

“Bill didn’t say much. He taught by example. He was my leader,” Mrs. Corrigan said. “I think about the words ‘preach the Gospel at all times. If necessary, use words.’ That is the way I think of Bill. He taught by example. He loved justice. He loved the poor. He tried to make things right in his own way, never telling anyone else what to do.”

The Corrigans met in the Navy during World War II and were married at the U.S. Naval Air Station in Jacksonville, Fla. Moving to Georgia he studied at Emory University and began to work at Lockheed-Martin. Following the Second Vatican Council, they studied the council documents in presentations given by the late Father Larry Hein, SJ, at St. Joseph Church in Marietta and, Mrs. Corrigan said, it transformed her sense of her Catholic faith and of the body of Christ.

“We joined the community of Christ Our Brother. We made a Christian community retreat at Ignatius House. It was really that retreat that made me see God a whole different way and the body of Christ—that God is here among us.”

They participated in the Poor Peoples Campaign in Washington, D.C., following the assassination of Dr. Martin Luther King Jr. Mr. Corrigan traveled to Haiti with Clergy and Laity Concerned of Decatur. After their first trip to Central America, Mr. Corrigan returned as an official vote observer in Nicaragua.

Employed for 35 years at Lockheed, he retired as an engineer in configuration control. While there he witnessed to the issues raised by his faith by placing articles on his desk, about the bishops’ peace pastoral or about Central America, Mrs. Corrigan said.

“Bill would put these articles on his desk and people would come over and read them . . . Pretty soon security would come down and look through his drawers and look at the articles.”

When he would return to his desk and hear about this, he treated it lightly, she said. “He would call security and say, ‘I hear you were down looking at my desk. Did you find anything that interested you?’ … He always handled things with humor. He never got angry. It was his great trait. He was always dignified.”

In 1999 the Corrigans received a parish Peace and Justice Award at the Catholic celebration in memory of Dr. King.

For his witness against the School of the Americas, Mr. Corrigan was given the Christian Service Award at Transfiguration Church in 1996, an annual award to a parishioner who displays a unique insight into the Lord’s call to serve others, especially the abused, forgotten or powerless.

“His witness should be a vivid reminder to all of us that we are called not only to hold deeply Christian values but also to live them in witness to the Gospel of love,” Msgr. Bishop said in making the award.

In addition to his wife, Mr. Corrigan is survived by three sons, Mike Corrigan of Macon, David Corrigan of Acworth and John Corrigan of Lake Oswego, Ore.; a daughter, Kathy Graham of Marietta; a sister, Margaret Etheridge of Pawtucket, R.I.; seven grandchildren and one great-grandchild.