[2] During World War II, Leslie served as an officer in the Irish Guards.

He fought in the Battle of France but was captured by German forces at Boulogne-sur-Mer, spending five years in various prisoner-of-war (POW) camps.

His military service earned him recognition, including the Legion d'Honneur, which was presented to him at the French embassy in Dublin on 9 November 2015.

[1] After the war, Leslie relocated to New York City and later spent time traveling throughout Europe, eventually settling in Rome.

At the age of 78, he returned to his family's ancestral home, Castle Leslie, in Ireland.