The five victims remain in critical but stable condition Friday morning.
Lorenzo Matthews, 11, and Michael Smith, 12, were at the barbershop. The boy's mother said her younger son was shot three times.
Chicago police said two men fired shots into the Gotcha Faded barbershop.
Police said two men walked into the packed shop, then walked out, pointed guns into the doorway and just started shooting.
"They exited the barbershop. They then pointed firearms into the doorway of the barbershop and started firing multiple times," said Chicago Police Dept. Deputy Chief Ernest Cato.
Three boys, ages 11, 12, and 16, were hit by bullets and two other men also wounded.
Cierra Mobley, the mother of two of the boys, is still in disbelief.
"It's their first time at the barbershop and it's somewhere that they really wanted to go. They were only there for like an hour before I got that phone call," Mobley said.
Mobley said Lorenzo had surgery late Thursday night.
An unidentified 16-year-old boy was shot in the hip and taken to Stroger Hospital in stable condition, police said.
Chicago police also said a 30-year-old man was shot in the arm. He took himself to a hospital, where's he's listed in stable condition.
A 40-year-old man is in stable condition at Mount Sinai Hospital after being shot in the thigh.
The corner barbershop is a popular spot for neighborhood families and children.
Customer Nicky Triplet said, "Kids always get their haircuts. Three kids got shot? That's, that's... it's senseless."
Police said detectives are poring over video from the barbershop and surrounding blocks, trying to identify the gunmen. A motive for the shooting remains unclear.