Marvin Wicker, 40, is wanted on multiple charges, including homicide by vehicle.
Philadelphia police say he was behind the wheel of a black Mercedes involved in the crash on Haverford Avenue on September 26.
Dawn Watson was killed as she crossed the road with her mother.
14-year-old killed in hit-and-run while walking with mother had recently moved to neighborhood
Wicker is considered armed and dangerous. Police say he may be operating a silver, two-door Chevy Cobalt.
He's known to frequent the 5900 block of Haverford Avenue.
Anyone with information can call or text police at 215-686-TIPS (8477).