Prince Carlo, Duke of Castro

In letters dated 21 July 2017, the Governor-General of Antigua and Barbuda issued notice that the Duke of Castro's 2014 appointment to the Order of the Nation had been annulled. The appointment of his wife was likewise annulled. In 2020, the branch of the Constantinian Order led by Prince Carlo was alleged to have influenced the election of Patricia Scotland as Commonwealth Secretary-General, which a spokesman for the Order denied, saying "These allegations are wholly offensive and wrong". It was alleged that Scotland used the Order's awards to influence votes in her favour, even though four of the five honoured national leaders had voted against her appointment.

In 2008, Carlo succeeded his father's claim as head of the House of the Two Sicilies. As claimed head of the house, he uses the title Duke of Castro. This claim is disputed by the Spanish branch of the House of the Two Sicilies. As claimant to the headship of the house, he thus also claims to be Sovereign of the Sacred Military Constantinian Order of Saint George as well as the Royal Order of Francis I.

On 31 October 1998, Prince Carlo married Camilla Crociani, and they have two children:

Prince Carlo of Bourbon-Two Sicilies, Duke of Castro (born 24 February 1963) is one of the two claimants to the headship of the House of Bourbon-Two Sicilies.

Carlo's supporters state that since his grandfather's brother Infante Carlos renounced his rights and those of his successors to succession to the throne of the Two Sicilies in 1900, the headship of the house passed to Carlo's grandfather Ranieri, Duke of Castro, then to Carlo's father Ferdinand, Duke of Castro, and most recently to Carlo. Nonetheless, this renunciation is deemed by detractors to not have been valid due to succession laws in Spain and the Two-Sicilies. Furthermore, Infante Carlos's claims to be the Duke of Calabria and head of the House of Bourbon-Two Sicilies were recognized by the Spanish Government through an official investigation commissioned by Juan Carlos I and carried out by the Ministry of Justice, the Royal Academy of Jurisprudence and Legislation, the National Research Council and the Council of State. After a thorough investigation, all the bodies reported unanimously to the king of Spain that the evidence suggested Infante Carlos and thus Prince Pedro were the legitimate claimants to the headship of the family. To date, this has been the only public official investigation devoted to resolving the matter, and thus the Kingdom of Spain does not recognise Prince Carlo as the rightful heir to the throne of the Two-Sicilies.