McClain, a native of Houlka, will begin his new role with the Golden Eagles on Oct. 1.
"Jeremy McClain is an absolutely fabulous addition to our athletics department," said Southern Miss AD Jeff Hammond.
In five seasons under McClain’s leadership, Delta State teams won eight Gulf South Conference championships, five NCAA regional crowns and made 21 NCAA postseason appearances – including national runners-up in football (2010) and baseball (2012).
“We appreciate the work Jeremy McClain has done,” DSU President Dr. John Hilpert said in a statement. “This is an excellent opportunity to further his career.”
Assistant AD for Development Ronnie Mayers, the former DSU swimming coach, will replace McClain on an interim basis.