He is voiced by Tony Amendola.
Shaun is the director of the Institute in 2287 and son of the Sole Survivor. During the outbreak of the Atom Bomb attacks, Shaun was only less than a year old. His parents(one of them being the main protagonist), took him and manage to the nearby Vault 111. Shaun and his parents were frozen into cryogenic stasis.
When the Institute discovered the records of Vault 111, they dispatched Conrad Kellogg, desperate for a non-corrupted DNA source, to revive Shaun and his parent. While Shaun's parent was resistant, he/she was killed by Kellogg. Shaun was then taken to the Institute, eventually becoming its director into (biological) age 60.