"I'm not in it for cash," Hall said. "I want no one else to go what I went through."
Known as "the atheist guy," Hall has been called immoral, a devil worshipper and - just as severe to some soldiers - gay, none of which, he says, is true. Hall even drove fellow soldiers to church in Iraq and paused while they prayed before meals.
"I see a name and rank and United States flag on their shoulder. That's what I believe everyone else should see," he said.
Hall, 23, was raised in a Protestant family in North Carolina and dropped out of school before earning his GED. It wasn't until after he joined the Army that he began questioning religion, eventually deciding he couldn't follow any faith.
But he feared how that would look to other soldiers.
"I was ashamed to say that I was an atheist," Hall said.
It eventually came out in Iraq in 2007, when he was in a firefight. Hall was a gunner on a Humvee, which took several bullets in its protective shield. Afterward, his commander asked whether he believed in God, Hall said.
"I said, 'No, but I believe in Plexiglas,"' Hall said. "I've never believed I was going to a happy place. You get one life. When I die, I'm worm food."
The issue came to a head when, according to Hall, a superior officer, Maj. Freddy J. Welborn, threatened to bring charges against him for trying to hold a meeting of atheists in Iraq. Welborn has denied Hall's allegations.
Hall said he had had enough but feared he wouldn't get support from Welborn's superiors. He turned to Mikey Weinstein and the Military Religious Freedom Foundation.
Weinstein is the foundation's president and a U.S. Air Force Academy graduate. He had previously sued the Air Force for acts he said illegally imposed Christianity on students at the academy, though that case was dismissed. He calls Hall a hero.
"The average American doesn't have enough intestinal fortitude to tell someone to shut up if they are talking in a movie theater," Weinstein said. "You know how hard it is to take on your chain of command? This isn't the shift manager at KFC."
Hall was in Qatar when the lawsuit was filed on Sept. 18 in federal court in Kansas City, Kan. Other soldiers learned of it and he feared for his own safety. Once, Hall said, a group of soldiers followed him, harassing him, but no one did anything to make it stop.
The Army told him it couldn't protect him and sent him back to Fort Riley. He resumed duties with a military police battalion. He believes his promotion to sergeant has been blocked because of his lawsuit, but he is a team leader responsible for two junior enlisted soldiers.
No one with Fort Riley, the Army or Defense Department would comment about Hall or the lawsuit. Each issued statements saying that discrimination will not be tolerated regardless of race, religion or gender.
"The Department respects (and supports by its policy) the rights of others to their own religious beliefs, including the right to hold no beliefs," said Eileen Lainez, a spokeswoman for the Department of Defense.
All three organizations said existing systems help soldiers "address and resolve any perceived unfair treatment."
Lt. Col. David Shurtleff, a Fort Riley chaplain, declined to discuss Hall's case but said chaplains accommodate all faiths as best they can. In most cases, religious issues can be worked out without jeopardizing military operations.
"When you're in Afghanistan and an IED blows up a Humvee, they aren't asking about a wounded soldier's faith," Shurtleff said.
Hall said he enjoys being a team leader but has been told that having faith would make him a better leader.
"I will take care of my soldiers. Nowhere does it say I have to pray with my soldiers, but I do have to make sure my soldiers' religious needs are met," he said.
"Religion brings comfort to a lot of people," he said. "Personally, I don't want it or need it. But I'm not going to get down on anybody else for it."
Hall leaves the Army in April 2009. He would like to find work with the National Park Service or Environmental Protection Agency, anything outdoors.
"I hope this doesn't define me," Hall said of his lawsuit. "It's just about time somebody said something."