Philippos was born at St Mary's Hospital, London, on 26 April 1986, the third son of King Constantine II and Queen Anne-Marie of Greece.

[2] He was baptized in the Greek Orthodox Church at Saint Sophia Cathedral, London, on 10 July 1986, with King Juan Carlos I of Spain, Prince Philip, Duke of Edinburgh,[3] Diana, Princess of Wales, Infanta Elena of Spain, Princess Benedikte of Denmark, Kyril, Prince of Preslav and Penelope, Lady Romsey serving as godparents.

[24] On September 28, 2024, Philippos served as a groomsman at the wedding of Princess Theodora of Greece and Denmark and Matthew Kumar at the Metropolitan Cathedral of Athens.

[26] The family was deprived of citizenship in 1994 when the former King Constantine refused to acquire a surname, as required by law for all Greek citizens.

Following the deposition of the Greek monarchy in 1973, the title "Prince of Greece" with the style of Royal Highness is no longer legally recognised by the government of the Hellenic Republic.