In 1960 Marangella was the chairman of the Baha'i National Spiritual Assembly of the Bahá'ís of France. When Mason Remey announced his claim to the Guardianship of the Baha'i Faith, Marangella recognised this claim. As a result Marangella was declared a "Covenant-Breaker" (a Bahá'í concept similar to the Christian notion of excommunication). Three members of the Spiritual Assembly of the Bahá'ís of France also recognised the claim of Remey, and the body itself was dissolved as a result by the body of the Hands of the Cause.
In 1961 Remey wrote a letter appointing Marangella to be the third Guardian of the Orthodox Bahai Faith. In 1964, Remey, who had previously set up the Second International Bahai Council seen as the embryonic Universal House of Justice, appointed Joel Bray Marangella to be its President. Mason Remey activated the Council in October 1965 thereby appointing and making Joel Bray Marangella the third Guardian.
Marangella serves as Guardian from 1965 until the present.