Calvin Hudson was an old friend of Benjamin Sisko, also known to Curzon Dax. They had joined Starfleet together, swearing to be captains by thirty and admirals by forty. At one point he was married to a woman named Gretchen who later died; they had no children. Following the establishment of the Demilitarised Zone between the Federation and the Cardassians, Hudson was assigned to the colonies there as a liaison officer. He soon came to see his posting as nothing more than a token position, believing the Federation had given up too much in ceding some of their colonies to the Cardassians, and arguing that the Federation would treat Cardassian colonists in their territory well whilst the Cardassians would not do the same to the Federation colonists. He also believed the Cardassians were secretly smuggling weapons to their colonists in the zone. At some point, he became one of the leaders of the Maquis, a terrorist group dedicated to driving the Cardassians out of the zone.
After the Maquis committed their first act of terrorism by destroying a Cardassian freighter leaving Deep Space 9, Hudson went to the station to meet with Sisko. He made his distaste for the treaty clear and was unconcerned about the Cardassians making aggressive moves since it suited them to stick to the treaty. He later received a visit from Sisko and Gul Dukat just as the Cardassians announced they had captured the Maquis member who planted the bomb on the freighter and he had died in custody. Hudson lamented having to talk to the man's wife and he and Sisko speculated the Cardassians were using a third party to smuggle in weapons.
After the Maquis kidnapped Dukat from Deep Space 9, Sisko, Kira and Bashir followed the ship's trail to a planet where they found Hudson leading a group of Maquis. Hudson made his allegiance clear and tried to convince Ben that the treaty wasn't enough to keep peace. When Sisko refused to be swayed from his loyalty to Starfleet, Hudson stunned him and the others and left. After rescuing Dukat, Sisko tracked Hudson down and offered him his Starfleet uniform back, saying he hadn't told his superiors of Hudson's involvement with the Maquis and they could still work together to end the violence in the colonies. Hudson responded by vaporising the uniform with his phaser.
Although Sisko and Dukat managed to stop the weapons smuggling, Hudson planned to attack a Cardassian colony which he believed was the location of a weapons depot. He attacked with two fighters, with the three runabouts from Deep Space 9 defending the colony. The resulting firefight saw the three runabouts disabled along with the other Maquis fighter, while Hudson's ship lost weapons, prompting Hudson to decide to pull out. Sisko locked weapons on Hudson's ship and tried to get him to surrender but Hudson refused, simply saying to get Starfleet to send someone else after him next time. Sisko let him go, still seeing him as a good man defending his home.
Sisko would not hear of Hudson again for three years until the episode "Blaze of Glory", when Michael Eddington, another old Starfleet colleague who had defected to the Maquis, told him that Hudson had died fighting the Cardassians.
Trivia
The original version of the two-parter had Sisko killing Hudson at the climax. Executive producer Michael Piller requested that Hudson be allowed to escape instead, which he later felt was a mistake.
