Founded in Chile by a group of exiles (chief among whom was Óscar Únzaga de la Vega), the FSB initially drew its inspiration from Spanish falangism.

A rather minor movement during the 1940s, the "Falange" began to attract major support from former landowners and other members of the Bolivian elite after the triumph of the 1952 Revolution, becoming the ruling MNR's main opposition party.

[3] FSB's growing popularity coincided, in particular, with a period of high inflation in the country under the presidency of Hernán Siles Zuazo (1956–1960),[6] and included many well-to-do university students.

[7] The movement was based on a cell system and so became stronger in some specific areas, notably in La Paz and Santa Cruz, although attempts to win over the peasantry in Cochabamba proved fruitless and damaged the party's growth.

[3] Nazi German war criminal and former SS-Hauptsturmführer Klaus Barbie settled in La Paz in 1951 and shortly afterwards witnessed a march by FSB members.

Barbie claimed that the sight of the uniformed, armband-wearing militants giving the Roman salute made him feel at home and he soon sought out leading members of the party and became close to them.

He garnered 15% of the vote in an election that many considered suspect due to massive state support for the government-endorsed candidate, Hernán Siles Zuazo.

[12] As aprt of the Christian Democratic Community it endorsed General Bernardino Bilbao Rioja's candidacy in the 1966 presidential election although René Barrientos of the ruling faction won easily.

With its leadership back in the hands of Mario Gutiérrez, FSB supported (as did the MNR) the 1971 military coup that brought to power General Hugo Banzer.