Together with his eldest brother Richard FitzGilbert, in 1066 Baldwin participated in the Norman Conquest of England.
Baldwin's fiefdom in Devon was the largest in that county,[3] listed in the Domesday Book of 1086 as comprising 176 holdings, mostly manors or estates, except the first two listed holdings which consisted of groups of houses in Exeter and Barnstaple.
[4] He is listed in the Domesday Book as "Baldvinus Vicecomes", literally translated as "Baldwin the Viscount", a Norman title signifying that he had an administrative responsibility over the county of Devon, which office had become almost synonymous with the Sheriff of Devon, an Anglo-Saxon office.
His first wife was named Albreda, whom Orderic Vitalis refers to as a daughter of the aunt of William the Conqueror, presumably niece of his mother Herleva.
[7] Following the deaths of his three sons without heirs, his daughter Adeliza was his ultimate sole heiress.