Raquelle Evans, 20, was arrested Tuesday night at a shelter in connection with the Parkchester incident on March 7.
Police are still searching for 19-year-old Travis Johnson.
Authorities say the attack began when the officer tried to arrest the pair for allegedly jumping the turnstile.
According to police, the officer caught up to the suspects and attempted to place them into custody when Johnson punched him in the face while Evans jumped on his back, knocking him to the ground before fleeing the station.
The officer sustained bruising and swelling to his face.
Evans is charged with assaulting a police officer, theft, resisting arrest, obstructing government administration and criminal trespass.