Deacon is a Railroad agent living in the Commonwealth in 2287, and a potential companion of the Sole Survivor.

Deacon is a spy for the elusive synth liberation organization, the Railroad. Little is known about his past prior to joining the Railroad, and he readily admits to lying about his own history. Among other things, he claims that he was among the first liberated Gen-3's, that he helped found the Railroad in the 2210s, and that he is the true leader of the organization with Desdemona serving as a figurehead.

The most detailed account that he provides holds that as a youth he was a member of the University Point Deathclaws, a gang which harassed accused synths. Their antagonism escalated to the lynching of a man suspected of being a Gen-3. Shaken by his part in the murder, Deacon left the gang to settle down as a farmer. Some time later he married a woman named Barbara. They intended to start a family, but the Deathclaws reemerged and attacked the farm. The gang had learned - to both Deacon's and Barbara's surprise - that Barbara was a synth.

Enraged by her execution, Deacon butchered the Deathclaws in a bloodthirsty haze. In the aftermath of the slaughter, he was contacted by the Railroad, who were evidently unaware of his prior affiliation with the UP Deathclaws. Despite believing himself undeserving, Deacon swore himself to their cause. As with most of his stories, there is no evidence to prove or disprove this claim.

Deacon may have served the organization as a runner under the name "John D" during and prior to November of 2266, and was among the few survivors of a devastating Institute attack that year. The following year, Wyatt accredited their "pyramid" structure of information distribution to John D's methods in the field, and in March of 2273 he was credited with the creation of the Railroad's "dead drop" system.

Sometime during or prior to December of 2273, he took the name "Deacon" and survived yet another Institute raid on the Railroad, with Pinky Thompson attributing the organization's survival to his escape plan. When Pinky stepped down in 2277, he aided Dr. Carrington and Desdemona in revising the organization's policies to put a focus on operational security.

By 2287, Deacon had became one of Desdemona's top men, carrying out important missions and escorting synths of high value to the Railroad. He had been assigned to work undercover, tracking persons of interest. At some point following the Sole Survivor's awakening, Deacon took an interest in the traveler, shadowing them throughout the Commonwealth and gathering information on their activities in the hopes of recruiting them for the Railroad.