Not much is known about Coolidge's background or early life except that they were a soldier in the United States Military.
In July of 2033, Coolidge was in a patrol with O.I.C. Waters, Private Atwater, and Private Shah on the outskirts of the Boston area. Atwater heard and/or saw an Infected near a collapsed office building, leading Coolidge and the others to investigate. However, they were soon attacked by multiple Infected, where Coolidge was killed.