In June 2331, Joseph Sisko fell in love with a woman named Sarah. Two months later, he married her and they had their child, Benjamin. Shortly after Benjamin's birth, Joseph was known to show off the newborn in one arm, while serving tables with the other. However, Sarah left Joseph and Ben after his first birthday. After Sarah was killed in a hovercraft accident in 2336, Joseph decided not to tell his son about her. (DS9 episode: "Image in the Sand")
In 2376, Joseph was expecting to be visited by his grandson Jake Sisko, although Jake disappeared into the Bajoran wormhole. Both he and Kasidy Yates learned that Jake was missing at the same time. (DS9 novels: Avatar, Book Two, Abyss)
After Benjamin disappeared, and later Jake, Joseph kept a precise record of how many days his son and grandson had been missing. The stress of the disappearances caused Joseph to collapse. He was found by Gabrielle Vicente. (DS9 novel: Cathedral)
Joseph recovered but became even more depressed. He was cheered by a visit by Miles O'Brien, Keiko O'Brien, Molly O'Brien and Kirayoshi O'Brien. He later asked the O'Briens to take him to Bajor. (DS9 novel: Lesser Evil)
In September 2376, he travelled to Bajor with Judith and the O'Briens to join Kasidy for the birth of her daughter, his granddaughter Rebecca Jae Sisko. He also found himself reunited with the previously missing grandson, Jake, and Benjamin, who had been journeying with Bajoran Prophets. (DS9 novel: Unity)
Sisko would often talk to Bey Toh when the Bajoran would visit his restaurant. In 2380, the topics included Bey's job as a speechwriter for Nanietta Bacco and Sisko's family. Sisko would often offer Bey encouragement when the scriptwriter discussed problems with his writings. (ST novel: Articles of the Federation)
Joseph died in 2381 shortly after the Borg invasion due to complications from his underlying medical conditions. He was cremated and buried at Katrina Memorial Cemetery in his native New Orleans. (ST - Typhon Pact novel: Rough Beasts of Empire)
In an alternate timeline in which Benjamin Sisko became trapped in a subspace field in 2372, Joseph invited his grandson Jake to live with him in New Orleans after his son's apparent death. Jake initially declined his grandfather's offer but was forced to accept it once Deep Space 9 was taken over by the Klingon Empire in 2373.
At Joseph's insistence, Jake and Azeni Korena married in Sisko's. The wedding guests included Kira Nerys, Jadzia Dax and Miles O'Brien. After Jake became a successful author, Joseph was extremely proud of his grandson and often boasted about him to his customers. Jake believed that Joseph was as proud of him as his father would have been.
In a permutation of the mirror universe in which the Terran Empire never fell, Joseph Sisko was the father of Fleet Captain Benjamin Sisko, the military governor of Bajor. Prior to 2377, he betrayed his son, leaving the younger Sisko with a scar across his sightless right eye. However, Benjamin was able to kill him.
In another parallel universe in which Earth was part of a planetary alliance known as the Celestial Union, Joseph Sisko and his wife were both killed during a savage war with the Tholians prior to 2377. Their son Benjamin served as a colonel in the war. (DS9 novel: Fearful Symmetry)
- DS9 episode: "A Time to Stand"
- DS9 - The Dominion War novel: Call to Arms...
- DS9 episode: "Far Beyond the Stars"
- DS9 novel: Hollow Men
- DS9 - Section 31 novel: Abyss
- DS9 - Mission Gamma novel: Cathedral
- DS9 - Mission Gamma novel: Lesser Evil
- DS9 novel: Unity