Jack O'Connell was the estranged father of Rick O'Connell, who left his family behind in search of other pursuits.
The father to the famed adventurer Rick O'Connell, Jack O'Connell left his family and, upon finding his son twenty years later, was estranged somewhat from him, and became closer to his grandson, Alex O'Connell, with whom Jack set off in a quest to find the famed Scarab Amulet. Jack reconciled with his son and gradually went on to find Medjai artifacts for the Medjai order.
Jack fathered Rick O'Connell in Chicago, Illinois but left when Rick was about ten years old because as a younger man, Jack had been marked as a Medjai, and Jack attempted to escape this newfound destiny, leaving his wife and son behind. Jack’s wife died when Rick was young, leaving the boy to be sent to different orphanages.
Throughout his travels, Jack learned many tricks and acquired many items to use in his further exploits, such as the knowledge of bullfighting in Madrid and a vial of acid acquired from an escape artist in Calcutta, and Jack went on to become an archaeologist for hire, finding antiquities and selling them off to the highest paying museums; Jack referred to himself as a "historical entrepreneur". For years, however, Jack was after one particular artifact, the Scarab Amulet, believing that finding the artifact would put him "on Easy Street".
One day in 1934 A.D, Jack was camping in the Sahara and found a young man wandering the deserts during a powerful sandstorm; the boy sank beneath the sands and was almost killed when Jack pulled him out, as the boy lost consciousness, and took him back to his campsite. Later in the night, when the boy came to, Jack stated that he saw the boy's flare and was lucky to find him in time before he was entombed in the sands; Jack then offered his kerchief to the boy, who blew his nose on it and handed it back to Jack, who preferred to just let Alex have it. Jack introduced himself simply as "Jack", and the boy responded with his name, Alex; Jack then asked Alex if he usually took trips to the most dangerous desert on Earth, to which Alex replied that it would hopefully be his last. Jack replied that he was on business as a "historical entrepreneur" that sought out ancient artifacts for collections around the world. Jack then noticed the ornate golden bracelet on Alex's wrist and asked how Alex had obtained it, to which Alex replied that it was a long story and told Jack, who stated that he had some free time to hear it.
The next morning, Jack's tent was buried in the sand, leaving Jack and Alex to dig their way out; Jack then led Alex on, stating that he left his gear elsewhere. The equipment was found being torn apart by three hungry hyenas that Jack remarked would have to be exceptionally hungry to be out hunting in the hottest part of the day.