artifact from attaching itself to a new host.
Early lifeEditWarehouse in 1955. Rebecca St. Clair was his partner, and though the two were initially antagonistic toward each other, they eventually fell in love and began dating; unbeknownst to them, this was due to the interference of an older, time-traveling Rebecca. He was a smoker and, like Pete, he got vibes.
On August 20, 1961, he and his partner, Rebecca, had been tracking an artifact that turned women into glass. On that date, he suffered a blackout that lasted twenty-two hours and nineteen minutes. In fact, the blackout had been caused by the fact that Pete Lattimer's mind had been sent back in time to inhabit Jack's body, while Myka Bering's mind was inhabiting Rebecca's body, in order to hunt down the glass transforming artifact at Rebecca's request. When Jack woke up, he was lying beneath a tree in a cherry orchard and was greeted with a kiss by Rebecca. He was initially surprised, because, up until that point, he and Rebecca constantly bickered and were mean to each other, but then he announced he should've done that a long time ago and returned the kiss. Unbeknownst to him, the first kiss had actually been while the mind of the Rebecca of 2010 had been in the body of the Rebecca of 1961. He kissed her back, and it was only after this that the Rebecca of 1961 had awoken, leaving the "older" Rebecca with the memory that their first kiss had taken place after they'd awoken in the cherry orchard.
The following year, Jack and Rebecca were called to Greenbury, Ohio, to investigate a supposed crashed flying saucer. During the course of their investigation, Rebecca reveals to Jack that she lives in fear that their Warehouse Agent lifestyle is going to lead to heartbreak in their relationship, which is shown as still going strong. Jack tells her they can't let that fear run their relationship. The "flying saucer" turns out to be a rocket built by Helena Wells in the late 19th century, powered by Joshua's Trumpet. When the trumpet starts disintegrating things in its path, Rebecca shoots it with a gun, seemingly destroying it; however, it was taken by a little boy Rebecca had been talking to earlier. Later, Jack and Rebecca discuss their relationship in the Bronze Sector, and Rebecca says that Jack was right about ignoring the fear.
Soon after that, Jack and Rebecca went to St. Louis to investigate several mysterious deaths by electrocution. As they were separated, the artifact responsible, the Spine of the Saracen, attached itself to Jack and attempted to control him. Unwilling to unleash the artifact on the public again, Jack sacrificed himself by sealing himself and the spine in the basement of the newly built police station, where the spine eventually drained and killed him. Rebecca searched for him, but was never able to find him again.
- The code for Jack's room in the Dead Agents Vault, 5485, is a slight rearrangement of the dates he was recruited to the United States Marines (1948) and the Warehouse (1955).