Star Trek Canon Special Note
Not everything listed in the origin is Canon. That is because only television shows and movies are considered canon for Star Trek. This being a comic website there are many things here that are not canon. So unless it is contradicted in film it should be listed as part of the character biography.
Benjamin Lafayette Sisko lost his wife Jennifer Sisko at Wolf 359 in the Borg attack on Earth led by Locutus. Afterward he sent his son, Jake Sisko returned to earth. Sisko remained in Starfleet as one of the top starship designers at Utopia Planitia above Mars. Three years later he was reassigned to Deep Space Nine a station built by Bajoran slavery under the ruthless tyranny of the Cardassians.
The character of Benjamin was created for the television show Star Trek: Deep Space Nine. It would be the first time a Star Trek show was commanded by a man of African origins as well as having a rank of Commander as appose to a Captains rank.
Now above the planet, Bajor, Sisko's mission is to help keep the peace between the federation, the Bajorans, and the Cardassians. His other goal is to prepare Bajor for entrance into the federation. He does the job to the best of his ability but after the death of his wife Jennifer he considers resigning his commission. When he meete Picard he tells him of this and Picard becomes concerned with him having this position. A big part of this is Sisko's hatred of Picard for the death of his wife. This is due to Picard actually being the very Locutus that attacked his ship at Wolf 359.
Sisko's job proves even more difficult when he is told by the religious leader of the Bajoran people that he is their Emissary as told by the prophecies. This makes Sisko a Religious leader. Later, Sisko and Jadzia Dax discover a stable wormhole leading to the Gamma Quadrant. This is believed to be the filling of the prophecies as the Emissary is suppose to discover the Celestial Temple. In other words the wormhole is believed to be the Celestial Temple.
The wormhole ends up being a connection to one of the greatest wars the Federation ever faced, the Dominion. The Dominion ended killing all ships and colonies in the Gamma Quadrant. Then it started pouring it's forces into Federation space and joined forces with Cardassia proclaiming war against the Federation and its allies. Sisko convinces the Bajorans to sign a non aggression pact with the Dominion to prevent it from destroyed. The war went on for years and took its toll on the promoted Captain Sisko.
The war got so bad that Sisko even abandoned his very beliefs and caused a situation which forced the Romulans to side with the federation in the war. Sisko also became more and more comfortable being the Emissary and became closer to the prophets. Perhaps the hardest parts in Sisko's life next to the death of Jennifer was when he found out his mother was a prophet, and being told that marring Kasidy Yates would end in disaster. After Sisko won the war against the Dominion he threw Dukat into a great fire and he joined the prophets in their Celestial Temple until the day when he would return to unite the Bajoran people.