It happened just before 2:30 a.m. Monday on the 7200 block of Woodland Avenue.
Officers say the suspect stole a 2024 Jeep Grand Cherokee with Pennsylvania tags reading MKZ-7506 and rear tinted windows.
The suspect was described as a man with a thin build and facial hair in his early 20s.
Investigators say he was wearing a black hooded sweatshirt with "Miscreant" and "Mentality" written in white lettering on the hood, black pants, dark-colored New Balance sneakers and armed with a black handgun with a long barrel.
According to police, the suspect frequents 71st and Elmwood streets as well as the surrounding area.
Anyone with information on the suspect or stolen vehicle is asked to contact the police at 215-686-8477.