Ukrainian reporter Vitalii Sediuk jumped over a barrier at the El Capitan Theatre in Los Angeles while Brad and partner Angelina Jolie were greeting fans on the red carpet.
The heartthrob was apparently unhurt and soon resumed signing autographs for fans.
A spokesman for the Los Angeles Police Department said: "He jumped over a barrier and made contact with Mr Pitt. I do not have the exact information of what kind of contact.
"He was arrested for battery and is being held in police custody.
"The man gave his name as Vitalii Sediuk. I understand he is a prankster and has been involved in similar incidents."
Witnesses saw the man, from the fan area, jump over a barrier on to the red carpet where he allegedly rushed at Brad, touching him briefly before security guards wrestled him back across the barrier.
Brad kept greeting fans and walked into the theatre.
His longtime partner Angelina Jolie stars in Maleficent, Disney's new live action spin on Sleeping Beauty.
Sediuk has a reputation for pulling stunts on celebrities.
Last week, he was caught on camera crawling under the skirt of Ugly Betty actress America Ferrera at the Cannes Film Festival.
At the SAG Awards in January he was pictured on his knees on the red carpet hugging Bradley Cooper's crotch.
He stormed the stage during the Grammys in 2013, running up to Jennifer Lopez and Pitbull to accept Adele's award for best pop solo performance before the singer reached the stairs.
And in 2012 Sediuk was slapped by Will Smith after he tried to kiss him on the lips at the Men In Black 3 premiere in Moscow.
