The Grammy Award-winning artist was convicted of setting up a cocaine deal in Florida in 2009. He was sentenced to a mandatory minimum of 15 years in jail at a June 23 hearing in Tampa court.
In court documents filed Thursday, Banton's attorney David Markus said a 15-year-sentence is "way more than necessary" in Banton's case.
Markus contends that Banton's limited participation in the drug deal, his work with charities in Jamaica and his otherwise clean record entitle the singer to a reduced sentence.
The documents include letters of support for Banton from actor Danny Glover, reggae singer Stephen Marley and Atlanta Hawks basketball player Etan Thomas.
Banton is also seeking an acquittal and a new trial.
The Associated Press contributed to this report.