She lost her husband to suicide in May 2006. She found her way up from the depths of despair in the years since, helping military families cope with devastating grief.
On May 23, 2006, Gallagher and her children had gone to Disneyland, a 30-mile drive from their house at Marine Corps Base Camp Pendleton in Southern California. Gunnery Sgt. James Gallagher, the childhood sweetheart she had married 20 years earlier, had remained home.
But she and her children were puzzled when they returned home and the front door was locked. The Gallagher's 12-year-old daughter, Erin, went around to the garage to get in. She found her father's body, hanging from the rafters.
"She thought he might be kidding, and said 'Daddy, Daddy, that's not funny,' " Mary Gallagher recalled.
Gallagher said her husband's death swept her and her children into despair. But she credits their decision to serve as volunteer grief counselors for other military families who have faced suicide with allowing her own family to regain its footing. She volunteers with Tragedy Assistance Program for Survivors, an Arlington, Va.-based nonprofit whose grief counselors helped her family endure in the months after her husband's death.
Since then, she has consoled the military families of suicide victims around the country -- including a half dozen on Long Island in the past year.
"I try to let them know they are not alone," said Gallagher.
She said she only realizes now the depth of isolation her husband felt in the months after returning from combat.
Less than two weeks after returning from Iraq, and with little time to decompress from the death of his fellow Marines, he was sent away from home for several months of military training.
Later, when his fellow Marines were preparing for another overseas deployment, Gallagher was told he would remain behind as a family readiness officer. The men he had provided for during dangerous times in Iraq would go on without him.
The change left her husband feeling ripped away from men he felt he could trust with his life, Mary Gallagher said.
"He was devastated," she said. "I knew he was sad. He had sad eyes, and seemed so tired. But did I see the signs of . . . [post-traumatic stress disorder]? Absolutely not. PTSD can be just as silent as it can be loud and obvious.