[4] Frederick Hankey served in the British Army in Ceylon (1800-1811) as an infantry officer (he attained the rank of colonel in the 15th Regiment of Foot)[5][6] He then became private secretary of Sir Thomas Maitland, Lord High Commissioner of the Ionian Islands and Governor of Malta, whom he had met while in Ceylon.

Hankey represented Maitland (who resided in Malta) in Corfu from 1817 to 1823, thus being often incorrectly referred as "governor of the Ionian Islands".

[4] Hankey remarried in December 1818 with a woman from Corfu, Mrs Catterina (or Catherine) Valarmo, Vaslamo or Varlamo, with who he had Thomasina-Ionia (1819-1900), who married Captain Charles F. Maxwell in 1839, and Frederick (1821-1882), who became a famous erotic writer.

[9][10] He achieved great respect for a sensitive diplomatic mission to the Vatican about the legal immunity that the Roman Catholic Church enjoyed on the Island of Malta,[11] in particular Naples' claim that he had the right to nominate any Bishops of Malta.

The Vatican would eventually come down on the side of the British, thanks in large part to Hankey's diplomatic intervention with Rome.