Married to Li Finnegan
Hayes Forrester Finnegan (grandson)
John "Finn" Finnegan (son; presumably with Sheila Carter)
Had an affair with and presumably impregnated Sheila Carter [circa 1990s]
Jack Finnegan is the adoptive father of doctor John "Finn" Finnegan, who lives in Malibu, California. Jack paid Finn a surprise visit and learned Finn was about to marry Steffy Forrester, the co-CEO of the Forrester Creations fashion dynasty. Jack supported Finn when he told Steffy that Jack had adopted him, but seemed nervous at Finn's wedding to Steffy. Jack confronted a veiled woman who showed up for the ceremony, only to find out it was Pam Douglas, Steffy's great-aunt. However, after the vows, Jack's jaw dropped when Finn came in with Sheila Carter, whom Finn introduced as the biological mother he had just met. Jack earned the ire of his wife, Li Finnegan, as he revealed that he'd known Sheila was Finn's real mom because Sheila had approached Jack when Finn was a baby. Jack was horrified to learn that Sheila was a convicted criminal, whose crimes included causing Steffy's mother, Taylor Hayes, to be presumed dead after Taylor and Sheila struggled over a gun.
Jack joined the Forresters in discouraging Finn from having any contact with Sheila and demanded that Sheila stay away. However, Jack found himself between a rock and a hard place when Sheila threatened to go public with the fact that Jack and Sheila had had an affair behind Li's back, which had produced Finn. Jack felt he had no choice but to honor Sheila's request to hold Finn's son, Hayes Forrester Finnegan, while Steffy was out of town, and cajoled Finn into allowing it. But when Steffy came home unexpectedly, Jack watched as Steffy threw Finn out of the house.