Staff Sgt. Camilo Mejia, 28, of Miami Beach, Fla., could go to prison for a year and receive a bad conduct discharge if convicted by a military jury at Fort Stewart.
The Florida National Guardsman in October on a two-week furlough to the United States. He was gone for five months before turning himself in to the Army in March.
He said his war experience made him decide to seek conscientious objector status.
The infantryman said he believes the war is unjust because it is about control of oil supplies. He also said he was upset over the death of civilians.
He said he was particularly upset over an incident in which his unit was ambushed and civilians were hit in the ensuing gunfire, and another in which he said an Iraqi boy died after confusion over which military doctor should treat him.
He also claimed he saw Iraqi prisoners treated "with great cruelty" when he was put in charge of processing detainees a year ago at al-Assad, an Iraqi air base occupied by U.S. forces.
Mejia filed the statements March 16, before the Iraqi prisoner scandal at the Abu Ghraib prison became public. Fort Stewart officials said they have forwarded his account to the Army.
In his objector application, Mejia said detainees were kept blindfolded and troops were ordered to use sleep-deprivation tactics to aid with interrogations.
He said prisoners were kept awake for up to 48 hours at a time, often by yelling at them or having them sit and stand for several minutes.
"When these techniques failed, we would bang on the wall with a huge sledgehammer ... or load a 9 mm pistol next to their ear," Mejia wrote.
"The way we treated these men was hard even for the soldiers, especially after realizing that many of these 'combatants' were no more than shepherds."
By Russ Bynum