Jock Ewing was the founder of Ewing Oil and the patriarch of the Ewing family. Jock's rival was Digger Barnes, who Jock had prviously been business partners with, but then supposedly cheated him out of a fortune.
Jock and Ellie Southworth married in 1937 and had three sons (J.R., Gary and Bobby) together. Later it turned out that Jock had a fourth son, Southfork Ranch foreman Ray Krebbs was revealed to be his illegitimate son from a romantic affair overseas during the war. After Jock had a hunting accident in the 1979-80 season, it was revealed that Miss Ellie was in fact Jock's second wife, with whom he had had an affair while still married to his first wife, Amanda Lewis. It was implied that Amanda may have been suffering from a mental illness during their marriage, so explaining Jock's decision to leave her for Miss Ellie. Amanda featured in one scene of one episode, in which she was approached to establish some facts about Jock's early life. It was also implied that Miss Ellie had been pregnant with J.R. at the time of her wedding to Jock. These events were confirmed in the TV movie Dallas: The Early Years.
Jock and Ellie briefly seperated in 1981 but reconciled and went on a second honeymoon to Paris. From there, Jock traveled to South America in the fall of 1981 for business reasons, and while flying back from Venezuala to Texas the helicopter he was in crashed into a lake. Jock's body was never found, but he was declared dead in the fall of 1982. The storyline involving Jock's death was necessitated by the death of actor Jim Davis.
In a storyline years later on the show, a man named Wes Parmalee, claiming to be Jock, turned up on Dallas. Parmalee (portrayed by Steve Forrest) said he had survived the accident, which necessitated plastic surgery. After trying to convince everyone he was Jock (even successfully passing a polygraph test) it was eventually explained that Parmalee was a fraud. Parmalee left Dallas for good. The reason Wes Parmalee was able to pass the polygraph test was because when he first arrived in Dallas, he was suffering from memory loss of his own and really believed he was Jock Ewing. It wasn't until later he got his memory back and came clean to Ellie with the truth and left town.