A Jackson County Circuit judge sentenced Aaron Sullivan to three years in prison for his role in the death of a girl on the Fourth of July.
He could have faced up to seven years in prison, but prosecutors had agreed to ask for a reduced sentence in exchange for his guilty plea.
Sullivan had pleaded guilty in December to involuntary manslaughter in connection with the 11-year-old girl's death.
The former part-time pool worker admitted that his gun was used to fire a stray bullet that pierced Blair Hannah Lane's neck. She collapsed as she danced during a Fourth of July party at her uncle's home.
Sullivan shook the hand of Blair's father after the sentencing. He has repeatedly apologized to the family for the pain he caused them.
"I made a bad judgment," he said.
Blair's mother, Michele DeMoss, said her daughter wouldn't want her to be mad at Sullivan, but each day is excruciating.
"I don't get to make her lunch. I don't get to get her ready for school. I don't get to make her hair appointments," she said.
The family had sought a tougher sentence.
"It's time people realize that a gun is not a toy and a bullet is meant to do two things: to maim and to kill, and that day it did," said DeMoss.
The judge gave Sullivan two weeks to get his affairs in order.
Sullivan owned the gun that he and three friends used to fire dozens of shots. They were at the Whispering Lakes Apartments, which is separated by a lake and woods from the home where Blair was.
It will never be known whether Sullivan or one of his friends fired the fatal bullet, but Sullivan was charged because it was his gun that was used. Sullivan, 50, lost his job at Whispering Lakes over the shooting.
The Missouri General Assembly is considering "Blair's Law," which would make it a felony to illegally discharge a firearm.
In a statement, Prosecutor Jean Peters Baker said Blair received justice.
"This is an extremely tragic case," she said. "There are no winners. But at a minimum, this should send a clear message to the community that recklessly shooting guns inside the city can carry tragic consequences, especially for innocent victims like Blair Lane."