Army Sgt. Chris Cooper, 28, casualty of Iraq war

In late 2004, Chris Cooper left the Marine Corps after four years of service, deciding to give civilian life a chance.

Updated: An earlier headline for this story referred to Cooper as an Army specialist. The headline was changed to reflect a posthumous promotion for Cooper to the rank of sergeant.

At one point, living in Oceanside, Cooper worked for a contractor renovating homes and commercial buildings. But military ways were hard to shake.

When he made a mistake on the job site, he would punish himself by doing push-ups, recalled Dave Moffat, the contractor who employed Cooper and rented him a room. At home, Cooper practiced packing a backpack and singing military cadences in his room.

“He couldn’t escape it,” Moffat said. “It was in his blood.”

Fifteen months after leaving the Marines, Cooper enlisted in the Army as an infantryman.

Christopher Michael Cooper, 28, an Army specialist, died Oct. 30 of injuries he sustained in a noncombat-related incident in Babil province, Iraq, according to a Department of Defense statement. Army officials said the death was under investigation and declined to comment further.

Cooper was born Oct. 18, 1981, in a suburb of St. Louis. His parents split up when he about 5, and the boy grew up with his mother and older sister, mostly in small towns near St. Louis.

Cooper was a shy youngster who loved skateboarding and music more than studying, his relatives said.

He dropped out of high school and appeared to be adrift until his sister told him about a boot camp-style program for dropouts run by the Missouri National Guard. She remembers making him promise that if he went, he wouldn’t join the military.

He thrived in the boot camp program, earning his high school equivalency diploma and developing an appreciation for military life.

One day in November 2000, Cooper told his mother he was planning to talk to a Marine recruiter. Don’t worry, he reassured her, he wasn’t planning on joining.

“He came back that afternoon and said, ‘I’m leaving after Thanksgiving,’ ” his mother, Sherry Kennon, said. “It was scary, but I supported him.”

In the Marines, Cooper was assigned as a crewman on an amphibious assault vehicle and was stationed at Camp Pendleton. He devoted himself to his job but felt frustrated that he was never promoted to sergeant, his sister, Lori Coachman, said. He eventually decided to leave the service.

On visits home to Missouri, Cooper enjoyed attending concerts with his sister, a music promoter, and had eclectic tastes, from classical to heavy metal. His favorite was punk, including bands like the Ramones, Dead Kennedys and Misfits, whose logo was tattooed on his right shoulder.

In February 2006, Cooper joined the Army and served as an infantry team leader in the 2nd Battalion, 28th Infantry Regiment, 172nd Infantry Brigade, which was stationed in Germany.

A former colleague, Chris Conover, recalled in a posting on the Daily Kos website that “Coop” had an ability to motivate fellow soldiers.

“He wasn’t one to bark orders or treat you . . . like he was better than you,” Conover wrote. “He was fair and impartial and embodied all the qualities that make a good noncommissioned officer.”

In late 2008, Cooper’s unit was deployed to Iraq. In phone calls back home, he complained about the heat, the sand and the unsanitary living conditions.

He last spoke to his sister in October, less than a week before he died. He was in good spirits, laughing at her 6-year-old daughter, Kayla, as she bounced around on a webcam. He was planning to leave Iraq to visit them in December. It would have been his first trip back in two years.

“I can’t wait to come home,” he told his sister.

Soon after his death, a package arrived at the family’s home near St. Louis. Cooper had sent it so he would have it when he arrived, his sister said.

Inside were flash cards to help him study for his sergeant test while home on leave.

The Army promoted him to the position after his death.

“He grew into a really good young man,” his mother said. “I was just proud that he made something of his life.”