The OSU assistant men's gymnastics coach was accused of hitting and kicking a taxi driver, damaging a cab window and refusing to pay a $23 fare, WNBS-TV, Columbus, reported Thursday.
Police said Hamm, 28, fell asleep as he was being driven home from downtown Columbus in a taxi driven by Abdinair Elmi.
"I was trying to take him home safely and come back my home safe but I don't know … something happened on the way," Elmi said.
Elmi said he called 911 when Hamm attacked him after refusing to pay for the ride home.
When responding officers asked Hamm how many drinks he had consumed, Hamm said he had "probably eight drinks."
Hamm was arrested but later was free on bond and is expected to be arraigned Sept. 15.
Hamm, a three-time Olympic medalist who won the all-around competition at the 2004 Olympic Games, was hired by Ohio State last year.