He was born in Nice, France. His father served as private secretary to Napoleon III. After the death of his father, Briffault and his Scottish-born mother emigrated to New Zealand. In May 1896 he married Anna Clarke; the couple had three children, Lister, Muriel, and Joan, born from 1897 to 1901. Briffault received his MB, ChB from the University of Dunedin in New Zealand in 1905 and commenced medical practice. After service on the Western Front during World War I, he settled in England, his wife having died. In the late 1920s he married again, to Herma Hoyt (1898-1981), an American writer and translator, best known for her English translations of modern French literature. The Briffaults became clients of the literary agent William Bradley and were befriended by his wife, Jenny. His book on the troubadours helped popularize the theory that they were heavily influenced by the poetry and music of Muslim Spain. Briffault debated marriage with Malinowski in the 1930s and corresponded with Bertrand Russell. He died in Hastings,Sussex, England on 11 December 1948.
Briffault is the author of several books, including:
Asked how to pronounce his name, Briffault told The Literary Digest: "Should be pronounced bree'-foh, without attempting to give it a French pronunciation." (Charles Earle Funk, What's the Name, Please?, Funk & Wagnalls, 1936.)