Deontay Wilder has been ordered to complete 60 hours of community service.
The WBC heavyweight champion was found guilty of misdemeanour marijuana possession. He was arrested in Alabama in June.
The 32-year-old American received a 30-day suspended sentence and two years of probation.
Wilder, who defends his title against Luis Ortiz on 3 March, has to perform the community service at a local YMCA.
He has been linked with a 2018 title unification bout with Britain's Anthony Joshua. Joshua, 28, is expected to make an announcement regarding a bout with New Zealand’s Joseph Parker, 26, to unify the IBF, WBA and WBO belts.