Fedora tells the Hattiesburg American that he will fill the position quickly.
He says Jackson decided to take a job as a strength coach for an unspecified basketball program.
Jackson was only on the Southern Miss staff for five months after joining the Golden Eagles following five years at Kansas. He started as a strength and conditioning coach for Kansas before moving up to the position of cornerbacks coach his final three years.
Jackson took the Southern Miss secondary job in February, replacing Travaris Robinson, who spent one season in Hattiesburg before joining Tommy Tuberville at Texas Tech.