Authorities said Simone-Monea Rogers succumbed to her injuries Wednesday evening.
The shooting happened just before 9 p.m. Tuesday on the 1900 block of West Ontario Street in the Tioga-Nicetown section of the city.
According to police, Rogers was playing on the basketball court of the Jerome Brown Playground with her brother and two friends when someone began shooting in their direction.
Officers found the 15-year-old female victim lying face down on the court. She had been shot twice in the head and was unresponsive.
Police announced Rogers' death on Friday morning.
A 33-year-old woman, who was also playing basketball, was shot in the leg. She was taken to the hospital in stable condition.
"They appear to be hit by stray bullets," Philadelphia Police Chief Inspector Frank Vanore said on Wednesday. "There was at least one possible 4-year-old also shooting a basketball there, so it's very scary and very disgusting that somebody would just fire into a crowd of people that have nothing to do with anything."
Police said Rogers frequented the Jerome Brown Playground and is well known to the staff.
"They say she's a really nice girl. She also lives one half a block away from this location where she was shot," said Chief Inspector Scott Small with the Philadelphia Police Department.
Small said the entire incident was captured on cameras at the playground.
"It's very tragic. It shows this 15-year-old female actively playing basketball, actually dribbling the basketball, when she suddenly collapses when she gets shot," said Small.
Police are trying to determine where the shots came from and are looking for information on a silver vehicle seen in the area. They are not certain if or how the silver vehicle is connected to the case.
"It appears, at this time, that she was struck by stray gunfire. I don't know anyone who would intentionally shoot at a 15-year-old girl playing basketball," said Small.