He studied law at the University of Montpellier and worked for the left-wing newspaper La Dépêche de Toulouse.
Bruguier served with the French Army during the First World War and was awarded the Croix de Guerre and Médaille militaire.
He stood for unsuccessfully in elections to the city council in 1919 and 1924 on lists backed by the SFIO and Radical Party.
He was elected to the French Senate to represent the Gard department in a by-election in 1924, sitting with the Democratic Left until he joined the SFIO, and finally to the city council the year following.
Having been re-elected in subsequent elections to the senate, Bruguier was still serving in July 1940 when he was one of the 80 who voted against the grant of special powers to Philippe Pétain and the creation of the Vichy régime.