Porter, 39, was arraigned early Monday morning on multiple charges after his Sunday night arrest. He is now free on a $25,000 bond.
Porter faces a felony aggravated assault charge along with counts of simple assault, resisting arrest, disorderly conduct and trespassing, according to court records. He was also cited for public drunkenness.
The alleged altercation with a doorman took place at The Flats on Carson, a popular nightspot in Pittsburgh. Security guards at the bar summoned an off-duty police officer who was working at a nearby restaurant.
The officer witnessed Porter assault the employee of the bar at around 9:30 p.m. on Sunday, according to Pittsburgh police.
"Once he arrived on the scene, the officer stopped the assault and arrested (Porter)" Pittsburgh police said in a statement Sunday night.
Porter was placed in handcuffs and transported to the Allegheny County Jail. His next court appearance is a preliminary hearing on Jan. 19.
"We are aware of an incident tonight involving Joey Porter," the Steelers said in a statement late Sunday night. "We are still gathering information as it pertains to the situation, and we will have no further comments until we get more details."
Porter, in his third season on the Steelers' coaching staff, was a star linebacker for Pittsburgh from 1999-2006 and played in 13 NFL seasons. He is in his second season as the outside linebackers coach.
The Steelers will travel to Kansas City to face the Chiefs on Sunday in the divisional round of the playoffs.