Sir John Leslie was presented with the Legion d'Honneur at the French embassy in Dublin on Monday.  The 98-year-old is a cousin of Winston Churchill.
During WW2, he commanded a section of the British Army in a battle to defend Boulogne Sur Mer from the Germans.
He was captured and spent five years in a German Prisoner of War (POW) camp.
Better known as Sir Jack, the veteran said he was accepting the award "on behalf of all soldiers from the island of Ireland who fought and died between the two great wars".
He is a member of an aristocratic family that owns Castle Leslie in the Republic of Ireland, the County Monaghan stately home that hosted the wedding of Beatles singer Paul McCartney and Heather Mills in 2002.
His grandmother was a sister of Churchill's mother, making him a first cousin once removed of the former British prime minister.
Sir Jack joined the British Army when he was 21, enlisting with the Irish Guards in 1937, two years before WW2 began.
During his time in POW camp, he risked his life to send a postcard to Churchill, asking his cousin to agree to a prisoner exchange in a bid to free some of his comrades who had become ill in captivity.
After travelling the world on his release at the end of the war, Sir Jack returned to live at Castle Leslie in his 70s, when he became a regular visitor to County Monaghan nightclubs.
The pensioner is famed for his love of dancing to rave music, and celebrated his 85th birthday in the world's biggest nightclub in Ibiza.
Now just weeks away from his 99th birthday, he was presented with the Legion d'Honneur by the French Minister for Veterans and Remembrance, Jean-Marc Todeschini.
The minster said Sir Jack epitomised "the friendship and the memory of the Irish soldier".
"You said you were only doing your duty," said Mr Todeschini.
"But it was far more than your duty that you accomplished because you committed your life for the survival of your country, of France, of Europe and of your comrades.
"For me it is an honour to convey to you today, such a special day for Ireland, the eternal recognition of France."
An Irish veteran of World War Two, famed for his aristocratic connections and love of disco dancing, has been awarded France's top military honour.