Apodaca: How much can one man and his family sacrifice for the U.S.?

It's often been said in the 10 years since the terrorist attacks of 9/11 that the world as we knew it had changed forever. But let's face it, the world changed far more for some than for others.

Gary Mathieson is one of those whose life was dramatically altered by the events of that horrible day.

Mathieson, a teacher in Newport-Mesa since 2004, is an Air Force reservist. His military service has taken him away from his family for months, sometimes years, at a time. It's been a strain on his finances and his teaching career, and a burden for his wife, who is also a Newport-Mesa teacher, and his daughter, who just turned 13.

But when the towers fell in New York, Mathieson understood immediately what it meant. At the time, he was teaching in Huntington Beach, and his eight-year stint in the Navy Reserve was due to end that December.

"Every reservist, once 9/11 hit, we knew we were at war," he said.

Mathieson decided to reenlist, this time in the Air Force. Since then, he has worked as a loadmaster — a job that requires him to calculate the weight and balance of a plane's cargo — and as a combat photographer.

He's served on missions ferrying wounded troops from Iraq and Afghanistan to military hospitals in Germany and the United States. He's helped deliver equipment overseas and bring the coffins of fallen comrades home.

It's difficult for someone like me to understand the physical and emotional toll that all of this must have had on Mathieson. Yet when I met with him last week, I was struck by his resilience, good humor and humility.

Mathieson was my younger son's seventh-grade physical education teacher at Corona del Mar High School a few years back. He's a well-loved presence at the school — popular with students for his easygoing manner, and with parents, who appreciate the effort he puts into photographing and videotaping school events.

He told me he was due to leave early Saturday morning for two weeks of additional training, and then he'll ship out again in November for eight months. School officials have been extremely supportive, he said, and that's made a huge difference.

"I'm blessed," he said. "I get to do two fantastic jobs."