Trotter, 63, was arrested in December after a .25 caliber Beretta handgun was noticed in a side pocket of his carry-on luggage at Chicago's O'Hare International Airport.
In a plea deal arranged with Cook County prosecutors, Judge Charles Burns sentenced Trotter to a year of court supervision and 60 hours of community service, the Chicago Tribune reported. Prosecutors dropped the original felony charge, of bringing a gun onto a plane.
His arrest provoked interest because, at the time, he was considered a front-runner to succeed outgoing U.S. Rep. Jesse Jackson Jr. Trotter dropped his bid to fill Jackson's seat after the arrest.
Notable deaths of 2014 [PHOTOS]
FAMU hazing ringleader guilty of manslaughter