Born in Saratoga Springs, New York, Donnelly is based in  Philadelphia. In November 2007 Donnelly began playing with keyboardist Terry Adams, a founder of NRBQ, in the Terry Adams Rock & Roll Quartet. Adams rechristened the band NRBQ in March 2011.
Donnelly's background is rooted in Saratoga Springs, New York, and he currently resides in Philadelphia. In November 2007, Donnelly formed a partnership with Terry Adams, a founding member of NRBQ, in the Terry Adams Rock & Roll Quartet. Two years later, Adams redefined the group as NRBQ in March 2011.