The 24-year-old has put pen-to-paper on a two-year contract at the Jakemans Community Stadium, having enjoyed a goal-laden spell in the West Midlands.
Donnelly netted 50 times for the Yeltz – in roughly a goal-every-other-game ratio.
He now makes the move into full-time football, having been part of the Halesowen side which missed out on promotion to Step 2 in the Southern League play-offs in April.
Donnelly’s move is subject to final Football Association and National League ratification.