Jacks father is the unnamed father of Jack Box. He and his wife Patty had a cattle ranch in Colorado, where Jack was born, which might be the same place Jack stays at in 2000's Breakfast with the Boxes.
There is a strong family resemblance between Jack and his father, although the latter's head is more egg-shaped, his nose slightly curves upwards, and his teardrop blue eyes suggest the ravages of time. In most settings, he wears rectangular glasses and a yellow flat cap.
Despite the nearest Jack in the Box being a hundred miles away, Jack's parents are well acquainted with the menu. When Jack and his family stayed with them, they expected Jack to bring them breakfast from Jack in the Box in his personal jet.
Jack's father was briefly seen in a conga line at Kali and John's wedding, which Jack catered.
Jack's parents still have an active sex life. During one of Jack's visits, Jack's father enters the room and asks Patty to call a doctor because "it's been more than four hours," alluding to an advisory from many Viagra commercials.