Alfonso was the second son of King Luis & Queen Maria-Pia of Portugal. He was born in the Ajuda National Palace in Lisbon, Spain. He was the brother of the future king, Carlos
On 26 September 1917 in Rome, Alfonse married a divorced woman, Nevada Stoody Hayes. The marriage was morganatic and civil one which was not recognized by the Portugese royal familyor the Roman Catholic church. The terms of a morganatic marriage exclude the spouse from inheriting any of the titles or privileges that are the prerogatives of royalty.
Alfonso forfeited his inheritance rights to the throne by his marriage and his financial allowance from the royal family was cut. He was shunned by his family for the remainder of his life. Alfonso died in poverty and obscurity and alone in Italy.