Marina was born in Athens on 13 December 1906, and was the third daughter of Nicholas of Greece and Denmark, the third son of George I of Greece, and Elena Vladimirovna of Russia, a granddaughter of Tsar Alexander II of Russia.
Marina met George, Duke of Kent, the son of George V, while visiting London in 1932, and the pair became engaged two years later. The wedding took place on 29 November 1934 at Westminster Abbey and was followed by a Greek ceremony in the private chapel at Buckingham Palace.
While George and Marina had three children, George was also rumoured to have fathered a son, Michael Temple Canfield, with an American socialite, Kiki Preston, who was a known drug addict. The boy was adopted by American publisher Cass Canfield, the first husband of Lee Radziwill, sister of Jacqueline Bouvier Kennedy. George had numerous affairs with both men and women before and during his marriage, and was said to have had affairs with musical star Jessie Matthews and Noël Coward, although this was later denied. It has also been alleged that George was addicted to cocaine and morphine, due to his association with Kiki Preston, and attempts were made by his brother, David, to cure him of it in the 1920s.
When World War II broke out, George was appointed as Royal Bencher of The Honourable Society of Lincoln’s Inn, a position previously occupied by his father, and granted a commission in the Royal Air Force as a group captain in 1937. On 25 August 1942, George died when the flying boat he was travelling on crashed into a hillside near Caithness, while en route to Iceland. Marina had given birth to their third child, Michael, six weeks prior.
After George’s death, Marina continued to carry out her official duties, including being President of the Wimbledon All England Lawn Tennis and Croquet Club for 26 years. In 1947, Marina’s cousin, Philip, married Princess Elizabeth of York, later Elizabeth II, making Marina also his aunt by marriage. Queen Elizabeth would later appoint Marina as her official representative when Ghana gained independence from Britain in March 1957, and again, in September 1966, when the British Protectorate of Bechuanaland became the new Republic of Botswana.
Marina died from a brain tumour at Kensington Palace on 27 August 1968 and she was buried in the Royal Burial Ground, Frogmore.