Brien is an anglicized form of the Irish given name Brian, which is derived from the Old Celtic element 'brigh' meaning 'strength' or 'power', and 'ant' meaning 'forefront'. It was originally used as a byname, referring to a strong or warlike individual. The name Brien gained popularity in England during the Middle Ages due to the Norman conquest of Ireland, when many Irish nobility adopted French names and titles. Today, Brien is still considered an alternate spelling of Brian, but it can also be found as a surname of Irish origin. Some notable individuals with the given name Brien include American actor Brien Perry and Canadian musician Brien Hermanson.
"Brien is quite rare, with only five babies given this name annually in 1983."