As he got older, Jack and his father started to clash more and more. Normal teenage rebellion combined with Jason's pensity to drink and his crotchety ways. When Nancy died, things just got worse. Jason drank with more frequency, further alienating Jack. Jamie, still in high school, struggled to keep things together. However, Jack, now in his early twenties, couldn't stand being around Jason and left Alaska.

The next few years remain a mystery, but it is known that Jack drifted aimlessly from one place to another, taking odd jobs. During a stint in the midwest, he met a woman by the name of April Stevens. After a brief courtship, the two believed themselves to be in love and got married. However, reality sunk in and the two realized, bitterly, that they were not meant to be. They divorced, with Jack paying little attention to the fine details of the settlement.

It was around this time that Jack got wind of his father's death. Trying to track Jamie down, he discovered that she was in Dallas, engaged to a Cliff Barnes. Both were suing the Dallas Ewings, each with documents that claimed a 1/3 ownership of Ewing Oil, from Jason and Digger Barnes, respectively. Travelling to Dallas, Jack met with a cold reception from Jamie, who was resentful of what she saw as his abandonment. Eventually, the two warmed up to each other and resumed a warm relationship. However, when Jamie married Cliff, Jack was not thrilled. He revealed himself to J.R. and Bobby, his cousins whom he never met, saying that he could give them evidence that would negate Cliff and Jamie's claims—and would, in exchange for 10% of Ewing Oil. With no other option, Bobby and J.R. agreed, each signing over 5% and giving Jack 10%.

Jack proceeded to tell the brothers of a man that he had encountered in his travels, an old friend of Jason and Digger's. Jack took Bobby and J.R. to visit this man, who knew all about the documents, and quickly added that HE had the documents that negated them---provided by Jock and signed by Digger and Jason! With this information, J.R. and Bobby were able to win the court case against Cliff and Jamie.

Jack remained on in Dallas, which was not pleasing to J.R. He wanted the 10% back. Jack was not thrilled when April showed up in town, having heard about his newfound wealth. She showed him a stipend in their divorce settlement that he overlooked: law allotted her,, 50% of his income for the year after they were divorced. That meant that whatever he currently had, she got half of---meaning 5% of Ewing Oil. Jack was not cooperative with her, but J.R. got wind of April's plight and agreed to help her if she sold him the 5%. April agreed.

Not wanting to deal with the situation, and growing bored of Dallas, Jack sold his 10% to Jamie---for one dollar. He gleefully presented April with her half of fifty cents. Angered, April swore revenge. Jack soon left town, halting April's court case, funded by J.R. However, with the death of Jamie in California, Jack was tracked down and briefly returned to Dallas, where the courts ruled that his sale of the 10% to Jamie, without consultation to April, who owned half, was fraudulent. She was granted the 5% and sold it to J.R.

The following occurred on Return to Southfork and Knots Landing Reborn

Jack left Dallas again and spent the next many years drifting. While in Canada many years later, he met a woman named Abby Sumner. There was an immediate attraction between the two of them. They began a passionate affair, and it wasn't until later that they realized their connection---Jack was related to Gary Ewing, Abby's ex-husband. Her relationship with Jack renewed Abby's interest with the Ewings of Dallas, and she set about a plan to acquire Ewing Oil---one that Jack was intregal in. She confided her plan to Jack, who agreed---after all, he was never a large fan of J.R.'s

Abby managed to wrestle 75% control of Ewing Oil away from Gary, who was then running it. When J.R. called her on the fact that she couldn't own the company because she wasn't legally a Ewing, Jack walked in, revealing that they were married! The thrill of the victory was short lived for Abby, but what was more disturbing was that she was starting to develop real feelings for Jack. He was in love with her, and she feared that she was falling in love with him (she had only planned to use him). After Gary convinced her to sign over the majority of her percentage to J.R., Abby committed herself to Jack, deciding to take a chance on happiness. Jack and Abby moved to Knots Landing, where they tried to resume as normal a life as possible, having retained a 7.5% interest in Ewing Oil.

Their time in Knots Landing remains vague, but it is known that things started to fizzle between them. Abby's constant work schedule, as well as her scheming, began to take a toll on their marriage. Eventually the two separated due to irreconcilable differences, and Jack took off for a vacation in the Bahamas. Abby did sign over the 7.5% of Ewing Oil fully over to Jack, though.

While there, he learned of a large piece of property across from Southfork that was on the market. He soon discovered that the land was oil-rich! Deciding to play a little joke on his cousin J.R., Jack purchased the land using a dummy corporation called "Jock Ewing Enterprises." When J.R. got wind of this, Jack flew to Dallas and revealed that he was the owner. J.R. was not pleased.

Jack was welcomed to Southfork by Miss Ellie, and he promptly left with the Ewings for the annual Oil Baron's Cruise. While there, Jack found himself immediately attracted to Sue Ellen, resulting in a subtle flirtation between the two of them. On the cruise, Cliff approached Jack about buying the 7.5%, but Jack was hesitant to give it up. Instead, he offered the oil rich land across from Southfork in exchange for a 5% interest in the Clifford Group. Cliff agreed.

Today, Jack remains at Southfork, working at the Clifford Group and fighting his attraction to Sue Ellen, which she doesn't want to admit is mutual.