Martin Pierce, 23, and Donnald Lindsey, 24, received lengthy sentences recommended by the prosecution for the 2008 death of Brandon Thompson, Pierce's nephew.
"It's always the worst when there's a completely innocent victim," Camden County Assistant Prosecutor Peter Crawford told Judge Michele Fox.
The judge agreed and sentenced Pierce to 42 years in prison even after his sister, the boy's mother, insisted Pierce was innocent and should get a lighter sentence. The judge sentenced Lindsey to 33 years.
Pierce will serve his sentence with no chance of parole for 33 years. Lindsey, who prosecutors say fired the fatal shot, also will serve prison time with no chance of parole - for 29 years.
Both men received credit for the nearly four years they have been in jail since they were arrested. Each must pay more than $6,800 in restitution to cover Brandon's funeral and the cost of moving his mother to another home.
Even in crime-ravaged Camden, the death of a young child like this is rare.
Both men were convicted in March of manslaughter - Pierce of first-degree and Lindsey of second - along with other crimes. Jurors heard during the trial how the men argued and called each other names, how they got guns, and when they saw each other in a neighborhood where children were playing, how they opened fire Aug. 4, 2008.
Authorities say Pierce fired his handgun 11 times, and Lindsey shot his semi-automatic gun 19 times. Neither man was struck. But the boy, out playing under his mother's watch, was hit in the head and died almost instantly.
In separate court hearings Wednesday, Pierce chose not to address the judge. Lindsey apologized to his family and to Brandon's and lamented that he won't be able to raise his children because of what he did. His lawyer said he would have been willing to plead guilty, but prosecutors withdrew a plea deal because Pierce refused to plead.
Brandon's mother, Stephanie Thompson, told the judge her younger brother was not in the shootout, despite evidence prosecutors presented that Pierce was there and fired the first shot.
"Only I bear the pain that a mother would bear," Thompson said, as she pleaded for a lighter sentence for her brother. "I feel that the judicial system has let me down."
Brandon's paternal grandparents asked for severe punishment for both men. The boy's grandfather, Harrison Davis, partly blamed a world where "you can get a gun easier than you can get a job."
"I wish with all my heart that we were not here," he said. "But we are."
As he asked for tough sentences, Crawford pointed to a collage that showed photos of the smiling little boy eating birthday cake, playing in the snow and dressed as Spider-Man.