Hardy, who played in 15 games the last two years for the Fighting Irish, had asked for and been granted his release from Notre Dame after last season. He had said he was transferring to Bowling Green, but the decision wasn't officially announced until Thursday.
Hardy, a native of Reynoldsburg, Ohio, who recently graduated with a degree in sociology from Notre Dame, started two games in 2013. He totaled 35 tackles in his career with the Fighting Irish.
He missed the first eight games of the 2014 season while the university investigated him and four other players for possible academic dishonesty.