He was the son of Emmanuel de Bernières and Princess Giulia of Juliana. He lived in Pisona with his parents and younger sister Martine. In 1943, his cousin Crown Prince Stefan died. Without an heir, King Danilo III chose André (the son of his eldest daughter) as heir apparent to the throne. This happened during the Italian invasion when André and his family where living in Yugoslavia and Egypt.
After the war, King Danilo III returned to Juliana, but the monarchy was abolished in 1946 and replaced by a republic. André then grew up in London and Paris. His mother died in 1957 and his father remarried three times.
From Danilo III's death in 1946 until his own death in 2011, André was regarded as the rightful King of Juliana by many monarchists. His royal name was Andrea I.
André himself married Cristina Domecq Anasagasti (1948). They had one son, David (1980), who succeeded him as pretendent of the Julianan monarchy.