Frank Simes was born in Aydın, İzmir, Turkey (then Ottoman Empire), on 10 July 1905. His parents were Frank Simes (1880–1934) and Pauline Karakulaki (1876–1927). He had at least five siblings: Francisca Vincentia (born 1898), Charles (1900–1900), Alice (1901–1995), Ann (1903–1946), and Eric Charles John (born 1909).
On 1 December 1932, he married Leontina Vittoria D’Isidoro (1908–2005) in St. John’s Cathedral in İzmir. They had two daughters: Anna Audrey and Antonia Winnie. From 1939 to 1970, he worked for the BBC World Service. He was fluent in Turkish.
Frank Simes passed away in Barnet, London, England, on 18 September 2016, at the age of 111 years, 70 days.
On 13 April 2016, following the passing of Harold Bracher, he became the oldest living man in the UK, at the age of 110 years, 278 days. Upon his own passing, he was succeeded by John Mansfield (14 December 1907 – 27 November 2016).
His age was validated by the European Supercentenarian Organisation (ESO) on 25 February 2020.