The girl was in critical but stable condition at St. Christopher's Hospital for Children, the Philadelphia Daily News reported. She was shot in the arm Saturday night while she was in her mother's arms.
Khalil Gilmore, 20, the alleged shooter, was also hospitalized at Temple University Hospital. Police said he was wounded in the half hour between the earlier shooting and his discovery by police.
Investigators say Gilmore wounded the baby while firing at another young man who was hit twice. The 21-year-old was treated at Temple.
"It's horrendous, it's despicable and it's deplorable what happened out there," East Detectives Capt. John Gallagher told the News.
Police said a federal prosecution of Gilmore would let the community know street shootings are being taken seriously. Gallagher said both Gilmore and his alleged target have records.
"Neither of these individuals is an innocent victim," he said. "The only innocent victim is the little girl who was shot."