Troy announced Hartwell's hiring Wednesday, and he'll be introduced in a news conference Friday.
The Mobile native has spent the past nine years at Ole Miss. He rose to senior executive associate athletic director.
Troy Chancellor Jack Hawkins says Hartwell "is an experienced leader who has the perfect combination of experience, qualifications and enthusiasm to lead Troy into a new era of athletic competition."
Athletic director Steve Dennis announced in July that he would resign at the end of September. He had led the department since 2005.