Brock Peters playing Joseph Sisko on Star Trek: Deep Space Nine was a welcome redemption for his previous role as the villainous Admiral Cartwright in Star Trek VI: The Undiscovered Country. Joseph Sisko is the father of Captain Benjamin Sisko (Avery Brooks) and the grandfather of Jake Sisko (Cirroc Lofton). A Creole gourmand who hated space travel, Joseph was happy as a clam living in New Orleans as the owner/operator of his family's restaurant Sisko's Creole Kitchen.
Joseph Sisko is a far cry from Star Trek fans' introduction to Brock Peters' talents in Star Trek VI: The Undiscovered Country. Admiral Cartwright was a powerful and influential Starfleet flag officer who conspired with Klingon General Chang (Christopher Plummer), the Romulan ambassador, and others to assassinate Klingon High Chancellor Gorkon (David Warner). Cartwright dreaded a future where the United Federation of Planets and the Klingon Empire were allies. Ironically, Cartwright allied himself with insidious Klingons and Starfleet co-conspirators like Lt. Valeris (Kim Cattrall) to try to prevent galactic peace. The plot was foiled by Captain James T. Kirk (William Shatner) and the crews of the Starship Enterprise and the USS Excelsior.
How DS9's Joseph Sisko Redeemed Brock Peters For Star Trek VI
Thankfully, Joseph Sisko on Star Trek: Deep Space Nine was a 180 for Brock Peters from Admiral Cartwright in Star Trek VI. Joseph was a moral man, a loving father and grandfather, and he taught Ben everything he knows in the kitchen. It was always a happy occasion when the Siskos visited Earth and spent time with Joseph in their restaurant. Of course, Joseph put Jake to work in the kitchen, and he was sure to give Ben wise counsel, including pointing out when Starfleet's orders were morally objectionable. Joseph's generosity extended to Jake's friend, Nog (Aron Eisenberg). Nog was thrilled to be a VIP guest at Sisko's Creole Kitchen when he was a Cadet at Starfleet Academy.
If Joseph Sisko had ever met Admiral Cartwright, he'd have taken the Starfleet Officer to task for his hardliner position on the Klingons and Cartwright's objections to galactic peace with the Federation's greatest enemies. In Star Trek VI, it was downright shocking to hear a Starfleet Admiral refer to the Klingons as "the alien trash of the galaxy," but this was just the tip of the iceberg as Cartwright's treasonous scheme to assassinate Gorkon was already underway. In contrast, Joseph abhorred and fought against Starfleet infringing on personal freedoms, like when they declared martial law on Earth out of fear of the Dominion's Changelings.
What Happened To Joseph Sisko After DS9?
It's unclear what canonically happened to Joseph Sisko after Star Trek: Deep Space Nine ended. At the conclusion of the Dominion War, Captain Sisko, the Emissary, became one with the Prophets and transformed into a being existing in non-linear space-time. Ben left Jake behind on Deep Space Nine, and his father back on Earth. Star Trek: Lower Decks' Ensigns dined at Sickos' Creole Kitchen a few years later, but Joseph, the proprietor, didn't appear. Lower Decks' crossover episode with DS9 also provided no updates on the Siskos. Joseph suffered from health problems, so it's possible he could have passed away at some point after DS9's series finale.
Sadly, Brock Peters passed away from pancreatic cancer in 2005, so Joseph Sisko is very unlikely to make further Star Trek appearances outside of a possible cameo in one of the animated Star Trek series. But Peters was a memorable Star Trek guest star who unforgettably portrayed characters on distinctly opposite sides of the moral spectrum. As Admiral Cartwright in Star Trek VI, Brock Peters played a very bad man, which makes his turnaround to portray the loving father of one of Star Trek's greatest Captains in Deep Space Nine all the more remarkable.