Officers have canvassed the neighborhood and reviewed video from the scene as the investigation continues.
The shooting occurred just before 7 p.m. on the 2300 block of South 64th Street near Glenmore Avenue.
Investigators believe the victim arrived in a blue minivan intending to fight someone near an alleyway. However, a third person was present with a gun.
"That fight did not take place prior to punches being thrown. I'm being told by officers on scene that reviewed the video footage that an individual in a black hoodie with a white emblem on it removed a firearm in anticipation of this individual showing up," Capt. Timothy Stephan said.
Police say the victim was taken to Penn Presbyterian Medical Center in critical condition.
The shooter ran from the scene and got away in a dark-colored Nissan and remains at large, according to police.
"When I came out, all I could see was chaos, people running everywhere. Next thing you know, I find out it's a good friend of mine that got shot over there," said Joe Davis, who lives nearby.
Police have not identified the victim, but Davis said he knows him well.
"He's a good guy, very good guy. He's a father, a hardworking man," Davis said. "I'm praying for his family and him."
Authorities are asking anyone with information to contact police at 215-686-TIPS.