We're leaving this godforsaken place today. I'm leading the exodus to the old government bunker at Lost Hills. I'm leaving this log behind to be buried when this place goes in the next exchange. Who knows, maybe someone will find it someday...”— Captain Maxson's diary
The team and research personnel were later relocated to the Mariposa Military Base in the year (January 7, 2077), where further FEV research was conducted. On October 10, when Maxson and his men learned about the human experiments going on in the base, the base morale suffered a hefty blow. The original leader of the security team, Colonel Robert Spindel, suffered a nervous breakdown and committed suicide, so Maxson assumed his command.
Captain Maxson then took control of the entire base and interrogated the scientists. After interrogating chief scientist Robert Anderson and learning what was really happening on the base, Maxson executed him. Five days later, Spindel committed suicide and Maxson ordered all the scientists executed. Confused and detached, Maxson declared himself and his men in full desertion from the army via radio. No answer came as the political situation was at its climax and the Great War was at hand.
The personnel families stationed outside the base were ordered to move in. Two days later, the bombs launched. Maxson and his men survived the war unharmed, safely sealed inside the Military base. After making sure the radiation levels outside were safe, Maxson ordered everyone to leave the accursed military base and travel to the Lost Hills government bunker. After burying the scientists, Maxson's soldiers and their families began the Exodus to Lost Hills. Raider attacks took a heavy toll of casualties, including Maxson's wife. His teenage son survived. Maxson and his men later formed the Brotherhood of Steel, and the Lost Hills facility served as their main base.
Maxson became the first High Elder of the Brotherhood of Steel, forming the orders of Knights, Scribes and Paladins. In 2097 his grandson, John Maxson was born. Roger Maxson eventually died of cancer in 2135 and his son, already an accomplished soldier, took up the role of the High Elder, which stayed with the Maxson family until John's death.
After his death, the Brotherhood regarded Roger Maxson as an almost holy figure. Two places are known to be named after either him or his descendants - Maxson, one of the states of the New California Republic, and Maxson Bunker, a Brotherhood of Steel outpost somewhere to the east of California.
The only known current living descendant of Roger Maxson is the young Arthur Maxson, who is living inside the Citadel in the Capital Wasteland, under the care of Owyn Lyons and the Capital Wasteland detachment of the Brotherhood of Steel.
Roger Maxson does not appear personally in any of the Fallout games, but is mentioned in holodisks and in Brotherhood of Steel dialogues.