After the bombs fell, Randy graduated from the Virginia Endurance and Survival Training center (later Camp Venture) along with several other Free Staters. He was friends with Ella Ames, accompanying her as she conducted her experiments on strangler pods, once shooting a gulper with his shotgun to protect her.
Randy was a member of Duncan McKann's failed expedition to track down ghouls from the Valley Galleria. When they cornered the ghouls and realized that they were harmless, sentient beings that just wanted to be left alone, Randy could not bring himself to kill them. He was shot by Nari Samir in the ensuing confrontation, but not before activating a distress beacon which is still operational years later.
Randy Calloway appears only in Fallout 76.