He was a trained agricultural engineer and was a founding member of the Cao Đài religion. He was a member of Emperor Bảo Đại’s political cabinet. Under President Ngô Đình Diệm’s rule, he was briefly jailed for mild dissidence but then released early when Diệm was assassinated. In the 1967 South Vietnamese presidential election, Phan finished third with 513,374 votes (10.8%).