Mark Williams, 33, of Crafton, was charged with riot, harassment and resisting arrest Monday in the altercation during his wedding cruise aboard the Gateway Clipper.
According to a criminal complaint, Williams touched the waitress several times, then scuffled with her boyfriend, whom she had phoned after the boat docked just before 1 a.m.
The groom's brother, off-duty state trooper David Williams, is accused of assaulting two Pittsburgh police officers called to the scene. David Williams, 35, of Plum, faces the same charges as the groom, plus obstructing law enforcement and disorderly conduct.
Mark Williams declined to comment to reporters outside court Monday.
State police spokeswoman Maria Finn confirmed that a trooper had been arrested during the reception. She said the trooper has worked for the state police since November 2003 and is assigned to the Kiski Valley barracks, about 30 miles northeast of Pittsburgh. He is on leave, she said.
A third man at the wedding reception is charged with punching out the window of a parked car.
The server's boyfriend acknowledged fighting with Mark Williams but wasn't criminally charged, police said.