Terms of the deal were not disclosed for the 26-year-old Clarett, who led the Buckeyes to a perfect 14-0 record and a national championship as a freshman in 2002 and later served a 3 1/2-year prison term.
"The team and I are excited to have Maurice Clarett join the Nighthawks family," Omaha Nighthawks head Coach Jeff Jagodzinski said. "He will be treated just like every other player on the roster and will be expected to perform to the best of his abilities both on and off the field."
Clarett never again played for the Buckeyes after his big season. He ran afoul of the law in 2003 for falsifying a police report after claiming that expensive merchandise was stolen from a car he had borrowed from a dealership.
Clarett was drafted by the Denver Broncos but was released during the team's 2005 training camp.
He was arrested on an armed robbery charge in 2006, which led to his prison stretch.