Johnny Gault is Tim Daly's character. He's sort of always refered to as Johnny Gault, rather than just Johnny.
His big secret pain is revealed after their first illicit kiss. They are herding her sheep for some reason and it's at night, Johnny emerges from the woods with an armful of firewood and in confession mode.
He tells Rebecca that he grew up in a Texas orphanage and every spring they'd get new clothes and a bath and the orphange would make them think they were being adopted, but really it was just farmer's looking for kids to work. Then one year, he was picked by a pig farmer, Mr. Cowper, who was harsh and beat him over everything (this explains the scarred back that Rebecca had seen earlier when she was saving Johnny Gault). Finally he got tired of it and went to run away but the pig famer set the dogs on him and drug him back and chained him up right under the place where the pigs are hung to die Then the pig farmer puts a pig up on the hook and sticks it and lets it bleed out, and I think on Johnny, as Mr. Cowper reads from the Bible until the pig dies. For two years Johnny was chained up until he could loosen a link in the chain and get free.
Then he went up to Mr. Cowper's bedroom and said "Pardon me, Mr. Cowper" and when he woke up Johnny stabbed him with a pitchfork, ran away, and kept on killing. "I'm good at it."