Police said security guards at The Flats on Carson summoned a police officer who was working nearby due to an unruly customer who was allegedly assaulting a doorman. The customer was later identified as Porter.
Porter was taken to Allegheny County Jail, police said. He is charged with aggravated assault, simple assault, resisting arrest, public drunkenness and terroristic threats. It's unclear whether Porter has an attorney who can comment on the charges.
The Steelers acknowledged an "incident involving Joey Porter" in a brief statement Sunday.
"We are still gathering information as it pertains to the situation, and we will have no further comment until we get more details," team spokesman Burt Lauten said.
Porter, who played eight of his 13 NFL seasons in Pittsburgh, is in his second season as the Steelers' outside linebackers coach.
Porter has had multiple run-ins with the law in the past, including a 2010 arrest for suspicion of drunken driving and an accusation of assaulting a police officer and resisting arrest. Those charges, filed in his hometown of Bakersfield, California, were eventually dropped.
Information from The Associated Press was used in this report.