John was the father of Alison Parker. He molested both Alison and her sister Meredith when they were children. Alison had blocked it out for most of her life, but remembered on her wedding day. John then threatened Alison if she told anyone and she ran, leaving Billy Campbell at the altar.
John later went after Alison and Meredith at Meredith's home, but Billy arrived in time to run him off.
After John won a legal proceeding, Alison confronted him at a barbecue and announced to everyone there what he did, causing everyone to get up and leave. John was not seen again on the series.