Steven Trotter, 33, pleaded guilty in an Ontario provincial court to staging an illegal stunt under the Niagara Parks Act. The prosecutor withdrew charges of mischief and trespassing on Thursday.
Trotter, a bartender from Fort Lauderdale, Florida, was fined C$5,000 (pounds 2,340) and ordered to pay C$515 in hospital costs for treatment of the minor injuries he suffered. He has been held in custody because he could not raise bail.
He and Lori Martin, a caterer from Georgia, went over the Horseshoe Falls on 18 June in a Styrofoam-covered glass fibre barrel. Ms Martin, who faces the same charges, has been released on bail.
Trotter is being detained by Canadian immigration officials for not stating the purpose of his visit when he crossed the border. He must attend an immigration hearing before returning home.
It was Trotter's second plunge over the falls. He performed a similar stunt 10 years ago in a pickle barrel and was subsequently fined C$500. Martin and Trotter were the second pair to survive a trip over the falls. Joseph De Bernardi and Jeffrey Petkovich made the trip in 1989.