In recent history, the preservation of the area's local heritage has been paramount among residents.This passion for Ærø was demonstrated in 2000, when the Marstal Maritime School was ordered to close.More than 2,000 islanders (a third of the island) travelled to Copenhagen to protest the closing of the historic school.
King Christian IV's cousin, also named Christian, was the Duke of Ærø from 1622 to 1633, and lived with his concubine Cathrine Griebels at Gråsten Manor House.
When the Duke died, a banner was found at Gråsten composed of nine pieces of cloth and in three colours – body colour, sea green, and golden yellow.
Gråsten Manor House was abolished in 1766 and the buildings were demolished. This is marked by the memorial stone at Olde Mølle (English = Ancient mill).
At the union, the old Code of Jutland from 1241 was applied and even today some of those rules are still valid.
Since 1 January 2006 the whole of Ærø has constituted a single municipality, known as Ærø Kommune.