Gerald J. "G.J." Cassidy was drawn to the military life early on. His favorite thing as a kid: playing army.

For many children, the appeal of a soldier's life soon fades at the thought of really being shot at, not to mention being ordered around and rising before dawn.

For Cassidy, it never lost its luster.

At his funeral Monday, he was remembered as a true soldier.

"A free nation cannot survive," Gov. Mitch Daniels said, "without people like Sgt. Cassidy."

Cassidy, 31, a sergeant in the Indiana National Guard, died Sept. 21 while stationed at Fort Knox, Ky. The cause of his death remains under investigation.

He was considered on active duty but was on a medical hold because of wounds he suffered in Iraq. In August 2006, a roadside bomb rocked the convoy he was commanding. Soldiers who served with him said he at first seemed unhurt after the blast but soon began complaining of frequent, painful headaches.

The Army declined to release details of his injuries, but his father, Gerald J. Cassidy, Lafayette, told the Lafayette Journal & Courier he suffered a severe concussion from the blast and was diagnosed with traumatic brain injury.

Monday, Cassidy was awarded the Purple Heart for his wounds.

Cassidy, a graduate of Carmel High School, grew up playing army around his family's home. "He and his cousin Ryan would roam around, finding 'bunkers' and attacking here and there," said his uncle Mike Cassidy. "It was always the USA vs. the Soviet Union, or G.I. Joe vs. Cobra."

As a teenager, Cassidy became more interested in battle strategy. He studied the Civil War. He painstakingly painted tiny toy soldiers in historically faithful uniforms and positioned them atop the family's pingpong table, re-enacting battles with his friends and second-guessing the generals.

He spent his summers at Culver Military Academy, in Northern Indiana, where he became a member of the Black Horse Troop, an elite equestrian detail. By age 17, he had achieved the title of adjutant commander.

That same year, Cassidy enlisted in the Army Reserve. Later he joined the Indiana National Guard and served with the Guard in Bosnia in 2004 and also in New Orleans after Hurricane Katrina.

He had attended Indiana University-Purdue University Indianapolis. He wanted to teach history after he retired from the Guard.

His time in Iraq was spent with the Minnesota National Guard. The Minnesotans had an opening, and Cassidy volunteered.

"How blessed we are to have people like Sgt. Cassidy, who volunteered to go in harm's way," said Maj. Gen. R. Martin Umbarger, adjutant general of the Indiana Guard.

Several dozen Guard personnel were among the hundreds who attended the service.

Pallbearers solemnly wheeled the flag-draped coffin out of Orchard Park Presbyterian Church in Carmel as "Onward Christian Soldiers" played.

Church bells tolled as the coffin glided into the hearse, which then proceeded to Hamilton Memorial Park Cemetery in Westfield for the burial.

At the time of his death, Cassidy was assigned to Fort Knox's Warrior Transition Unit, which helps soldiers having difficulty making the move back to civilian life.

Cassidy was found dead in his room, but the cause of his death remains unclear.

"The autopsy is still awaiting some results," said Ken Beyer, a Fort Knox spokesman.

Cassidy leaves behind a wife, Melissa Castillo Cassidy, and two children, Abbey, 5, and Isaac, 3.