It happened around 3:30 p.m. Wednesday.
Deputy Commissioner Joe Sullivan said the gunfire came from the backseat of a red or maroon Pontiac G6.
"Another child has been hit with gunfire at the hands of a coward," said Sullivan.
On Thursday morning, Philadelphia police released numerous surveillance images of the vehicle.
WATCH: VIDEO CAPTURES MOMENT GUNMAN OPENS FIRE, INJURING BOY
The boy, who family members identified as Semaj O'Branty, fell to the sidewalk after being shot.
Witness Harry Stork said he saw a woman trying to save the boy's life.
"She cupped his head and tried to stop the bleeding and they took him to the hospital," said Stork.
O'Branty was rushed to the hospital in critical but stable condition. He is expected to survive.
Immediately after the shooting, dozens of Philadelphia officers were deployed around the city to find the red Pontiac.
Sullivan vowed to use all department resources to find the vehicle.
"This is unacceptable. We have to join police and community, come together and work together to get people like this off the street before another one of our children are injured," said Sullivan.
Philadelphia Police Captain John Walker said a person who shot back at the Pontiac has been taken into custody, but the shooter remains at large. Walker said they've recovered that man's gun inside a recycling bin.
Around 8 p.m. members from O'Branty's church came out to sing and pray for him. They say the 10-year-old, who has two sisters including one twin, loves to volunteer.
"He'd put his apron on and gloves and he'll serve the kids the food," said Pastor Richard Smith with Faith Assembly of God.
The pastor also had some words he hoped somehow the boy would hear.
"I love him. I'm holding on with God for him and he's going to be OK," said Smith.
Anyone with any information is asked to call police at 215-686-TIPS.