Peter was a petty criminal that committed breaking and entering as well as had a few DUI's. Peter then learned that he had a son named Rick who lived in Midvale, but his mother had beat and mistreated him. When Rick learned about him, he sought him out and Peter took custody of him and moved him away from Midvale. Peter did what he could to provide for them, with great difficulty, but his son appreciated his efforts. Peter eventually went and found the money to send Rick to college. Then Peter had killed two people which he confessed to doing. His son spoke during his trial but Peter was given a life sentence.
Peter was then visited by J'onn J'onzz, Maggie Sawyer and Kara Danvers. They told him that someone was demanding his release from prison which Peter was a little surprised about. When they asked who it was, he told them he didn't know though he was very sarcastic about it. That set Kara off as the one that demanded his release had kidnapped her sister. He didn't know that J'onn was reading his mind to learn that he really didn't know who was behind this.
It turned out that it was his son Rick that was behind this. He had learned Supergirl's identity and was using his sister to try and break him free from prison by threatening to kill her. Maggie went to the prison to free him but Supergirl stopped her. She then went to Peter and told him what Rick was doing. Supergirl told him that even though he made mistakes in his life, the one good thing he did was be a good father to Rick. She told him that if Rick killed Alex then he would never come back from that. Peter then told the two of them where he thought that Rick would take Alex. They managed to arrive in time and save her.