- "If I was wrong, then I was wrong. I'd rather do something and make a mistake than be frightened into doing nothing."
- – Rev. Dexter
William Dexter was born in 2210 and began "serving the Lord" at age 10, which may mean he was ordained a preacher at that age. When he was a young man, he married a woman named Emily.
During the Earth-Minbari War he served as a chaplain in Earthforce. This experience gave him insight into what makes a good commanding officer, as he would relate to Captain John Sheridan years later.
At some point in his life, he met Brother Theo Ankises, a Trappist monk. Despite their different preaching styles and their incessant teasing, they were close friends. After the Earth Alliance Civil War broke out in 2260, Theo contacted Rev. Dexter and asked him to help Babylon 5 gather information against President Clark. Working with Rashid Abdul and Rabbi Leo Mayers, they smuggled the requested information to Babylon 5 under the guise of a missionary trip.
While on the station, Dexter gave some counsel to Captain Sheridan, who had been bowed under the stress of the civil war and the Second Shadow War, specifically regarding Delenn. Rev. Dexter gently suggested that Sheridan needed someone to talk to and empty his "worry tank" every now and then, and that Delenn was just such a person. Sheridan resented being told this, but as Dexter got up to leave, he said that when he and his wife were dating, she would come by his apartment and help him house clean, because it was her way of helping. This suggested to the Captain indirectly that Delenn was there for him, and that he did not carry his burdens alone. Dexter also asked to put on a Baptist prayer service. Despite Brother Theo's request that it be a "nice, quiet, dignified prayer service," Dexter led a traditional Baptist ceremony, including a loud rendition of "There's No Hiding Place Down Here."