Banton's attorney, David O. Markus, argued that a government informant had improperly entrapped the Grammy-winning singer.
A three-judge panel of the 11th Circuit Court of Appeals in Atlanta ruled Thursday that the evidence supported Banton's 2011 conviction in Tampa federal court.
The panel also agreed with the jury's conviction of Banton on a gun possession charge, which the trial judge had dismissed after the verdict was read. The judges rejected Banton's argument that his right to a speedy trial had been violated.
Banton's real name is Mark Myrie. He's serving a 10-year prison sentence. Markus says he believes "a good man is in jail for talking a big game."