Kenneth Walker "has already sustained life-long trauma, still fears harm from those who consider him a danger and seek to take away his freedom again," according to a complaint filed by his lawyer, Steve Romines, in Jefferson County District Court.
Louisville police Sgt. Lamont Washington told NBC News they do not comment on pending litigation.
The county attorney, who represents the city in civil litigation, did not immediately respond to requests for comment. A spokeswoman for Mayor Greg Fischer declined to specifically address claims in the civil complaint.
"We’ve not seen the lawsuit and cannot comment on the specifics of pending litigation," Fischer's Director of Communications Jean Porter said in a statement.
"But as the mayor has said, Breonna Taylor's death was a tragedy, and justice, peace and healing are what is needed for her, for her loved ones and for our community."
Taylor and Walker, a former EMT, were in her apartment just before 1 a.m. on March 13, when three plainclothes officers with the Louisville Metro Police Department arrived to execute a search warrant in a drug case.
"They refused to answer when we yelled, 'Who is it?'" Walker told reporters Tuesday on the courthouse steps. "Fifteen minutes later, Breonna was dead from a hail of police gunfire and I was in police custody."
Romines said the defendants have to be held liable for the botched raid.
"They said there's drugs there. There's no drugs there. They said there's money there. There's no money there," Romines said.
"Everything that they said about this was false. And yet they (said) 'Well no harm, no foul.' No. There has to be consequences."
The two believed the apartment was being broken into when police busted through the door, according to Walker and a previous lawsuit by Taylor's mother, Tamika Palmer.
Walker grabbed a gun and fired, shooting an officer in the leg. He had a license to carry and kept firearms in the home, and Taylor was unarmed, according to the lawsuit brought by Taylor’s family.
"That’s when Kenny heard the police yell at him — and that’s when Kenny realized the police were the perpetrators," according to Tuesday's civil complaint. "Although Breonna’s life tragically ended that morning, Kenny’s nightmare had just begun."
Walker was initially charged with attempted murder, but that count was dropped.
"The charges brought against me were meant to silence me and cover up Breonna's murder," Walker said. "For her and those that I love, I can no longer remain silent."
One Louisville police officer involved in the shooting, Brett Hankison, was fired. Two other officers involved were reassigned while an investigation is ongoing.
Even though charges were dropped against Walker, his lawyers fear that authorities could still go after him.
"His entire life has been changed," said Frederick Moore, another one of Walker's lawyers.
"Not only is the love of his life gone ... but let's also talk about the potential psychological effects of being shot at, that many times in the dark and the trust or lack thereof now for the criminal justice system and how they treated him."
Taylor's slaying and the death of Georgie Floyd, while in custody of Minneapolis officers, has sparked a summer-long series of protests across America, calling for police reform and other actions against systemic racism.