Colonel Jacob Kane is the father of Kate Kane and Beth Kane. He is a member of the prominent Kane Family, and is the uncle of Bruce Wayne by way of his late sister Martha.
A lifelong soldier, Jacob had been a field officer with USSOCOM for most of his career, leading numerous tactical operations across the globe as part of the 3rd Special Forces Group. His wife Gabi Kane was a Captain with the 525th Battlefield Surveillance Brigade. Both Kanes worked extensively with military intelligence services.
The Kanes often moved due to the nature of Jacob and Gabi's work. Jacob was frequently away from home, since his duties included intervention in various international military crises.
They eventually moved from Fort Bragg, North Carolina to Brussels, Belgium, since the parents were now serving in NATO. However, the family was soon torn apart due to a terrorist attack. Gabi took her daughters out to celebrate their twelfth birthday, and they were kidnapped by heavily armed men. Military intelligence eventually located the hostages, and Jacob was put in charge of the tactical unit sent to rescue them. However, they were too late, as his wife had been executed and his daughter Elizabeth was believed to be dead. He rescued Kate himself, but she was traumatized by the sight of her dead mother and sister.
In the wake of the tragedy, Jacob kept himself emotionally stable, a trait which Kate desired to emulate and eventually succeeded in. It inspired her to follow him into a career in the Army. Jacob taught Kate how to box when she was a teenager, likely related to her dream of military service.
By the time Kate was accepted into the United States Military Academy, Jacob's position within the Department of Defense was high enough that he was able to be more present in Kate's life. He accompanied her to R-Day when she was an incoming freshman, and during Kate's junior year attended her championship boxing match against Sophie Moore at the annual Brigade Boxing Open, during which he gave Kate ringside coaching that helped her win the title. Around this time, Jacob was also seeing a woman who would become his second wife, Catherine Hamilton.
Kate's resignation from the academy early into her senior year for DADT-related allegations came as an unpleasant surprise to Jacob, but his support toward his daughter after she came out to him was immediate. He expressed pride in Kate's integrity, but also worry for her future, as military service had been Kate's only plan for her life.
After a few years of watching Kate's life spiral downward into alcohol abuse and apathy, Jacob learned that Kate had started working as a vigilante relatively recently. Angry and afraid for her safety, he confronted Kate about this, but agreed to help organize better training for her when he realized how dedicated she was. Using the Murder of Crows, an informal band of some of his old friends in the special operations community, Jacob constructed a two-year training program for Kate, while revamping her headquarters and designing her Batwoman suit in the meantime.