"And beginning a new one."
Lieutenant commander Calvin "Cal" Hudson was a male Human Starfleet officer of the 24th century. He married Gretchen Hudson. He gained distinction for being Starfleet's first attaché to the Federation colonies in the Demilitarized Zone, but later fought for the Maquis until his death.
Hudson and Benjamin Sisko were close personal friends, having graduated from Starfleet Academy together in 2354. At New Berlin, the two spent time together with their wives, including at a Mazurka Festival. He also knew Curzon Dax, who was privy to personal information concerning the officer. He was married to Gretchen Hudson for several years until she died in the late 2360s.
Hudson was like his friend Benjamin Sisko in many ways; he was an experienced officer and an able leader who seemed to inspire trust in those he worked with. Hudson, however, was leading a double life after the Federation-Cardassian Treaty in 2370; although assigned by Starfleet as the attaché to the planets in the Demilitarized Zone, he was an influential leader of the Maquis. After seeing the suffering and abuse of the colonists by the Cardassians, he joined the separatist organization and used his Starfleet position to secure intelligence and supplies for them.
Commander Sisko uncovered Hudson's deception while investigating the destructive implosion of the Bok'Nor and a recent kidnapping of Gul Dukat. At first, Calvin wanted his friend's covert assistance by allowing the rebel force to use DS9 as a repair station for their ships, expressing that it would have been nice to work closely once again; Sisko angrily refused and the two parted ways. Subsequently, Hudson led an attack wing of Maquis ships against three Starfleet runabouts, managing to hold his own and finally escape. (DS9: "The Maquis, Part I", "The Maquis, Part II")
Hudson died in a skirmish with the Cardassians while fighting for the Maquis in 2373, and was described by fellow Starfleet defector Michael Eddington as a martyr for the cause. Despite their enmity, Sisko was deeply saddened by news of Hudson's death. (DS9: "Blaze of Glory")
Calvin Hudson was played by Bernie Casey.
The character was originally conceived as the main focal point of "The Maquis" two-parter, as Ira Steven Behr later noted; "We thought 'The Maquis' was the Cal Hudson Show." While penning the duology, the writers found Hudson should be less involved in the story. "So we killed Cal Hudson at the end," said Behr. Michael Piller subsequently vetoed this plan, though. "Michael came to me," Behr continued, "and said, 'No, not this time. We need this character. We're not going to ruin another guest star; you killed [Li Nalas as played by] Richard Beymer [in "The Siege"] and you're not going to kill Cal Hudson.' I said OK. Well, it got to the point during dailies where Michael looked up at me and said, 'We should have killed Cal Hudson.'" (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p. 73)
Bernie Casey commented: "The episodes are really about whether or not the integrity of their friendship will be put asunder by a circumstance neither man wants but one in which each man believes he's right. It's like the situation in Bosnia. It's bestial, mean and horrendous because both sides think they're right. I found it rather fascinating to deal with all of that within the episode's story, and would certainly consider any offer to participate in Star Trek: Voyager.". 
According to a cut line from DS9: "The Maquis, Part II", Curzon Dax once persuaded Hudson and Sisko to play a game of dom-jot against two Zakdorn on Pelios Station. The Zakdorn won each game played over seven hours and Curzon revealed he had bet on their victory. (Star Trek: Deep Space Nine Companion - A Series Guide and Script Library)
Hudson appears in the The Lives of Dax short story "The Music Between the Notes", which is set on Pelios Station. Hudson also appears in the The Brave and the Bold, Book Two and in the DS9 comic "Public Enemies, Private Lives".