The car was parked in the 7300-block of South Eberhart Ave. on the city's South Side. The gunshots shattered the car's windows and struck Butler several times in the chest.
Butler's girlfriend, Tajuana Harrell, said he was a family man.
"Family was like the entire world to him. So, I don't know why anyone would want to harm him," Harrell said.
"I still can't believe it, and the hardest part is saying something to my granddaughter about it," said the victim's father, Tommie Carroll.
Witnesses say the person who shot Butler was in a pick-up truck, which may have been red.
Anyone with information is asked to contact Chicago police.