Age 63, of South Fayette, on August 8, 2025. Beloved husband of Christine (Scheidter) Hartz; loving father of Danny (Maci Caster) Hartz; cherished son of Carl and the late Sherrie Hartz; brother of Gary (Julie) Hartz; uncle of Tom (Megan) Nelson; great uncle of Ryder and Jaxon Nelson also survived by his four-legged best friend Jessie. Gregg was a retired machinist from Union Electric Steel, Carnegie, PA. Family and friends received on Monday from 2-4 and 6-8 PM at the Warchol Funeral Home Inc., 3060 Washington Pike, Bridgeville (412.221.3333), where a funeral service will be held on Tuesday at 11 AM. Memorial donations may be made to St. Jude Children’s Research Hospital.