Porter, 23, is in custody at the NYPD's 17th precinct in Midtown.
Porter returned early Monday morning from an evening out to the Millennium Hotel, where he and his girlfriend were staying.
According to police sources, the victim was upset with the late hour of his return and locked the door.
Once he entered with the help of hotel security, Porter is accused of beating up the woman, the sources said.
The extent of the victim's injuries was not immediately clear.
Domestic assault charges are pending against Porter.