The infant Archduke and Crown Prince Franz Josef's first birthday was celebrated in Ischl on 18 August 1831, in a house on the Kreuzplatz, where his young mother Sophie tended him personally on the sunny balcony overlooking the street. The nature of the celebration has not been recorded, but the birthdays of members of the imperial family were invariably occasions for public festivities. In this case there was the added incentive for jubilation that the long-awaited heir to the throne had at last arrived.

From around 1834 Franz Josef celebrated every birthday as Crown Prince while resident in the Seeauer house (now the town museum) on the Esplanade in Ischl. He missed his 18th birthday in Ischl in August 1848, due to the revolutions throughout the Monarchy, but with one exception thereafter (the 1878 Balkan crisis) he spent every birthday of his life in Ischl up to 1913. The annual jubilation attained imperial dimensions after he became Emperor on 8 December 1848, as the photographic evidence of the celebrations demonstrates.

The first Kaisermesse was celebrated in the parish church in 1849 in the Emperor's presence. After the completion of the Kaiservilla during the 1850s, the Kaiserpark was opened to the public every year on 18 August, and every prominent personality in Ischl and the Salzkammergut attended to offer personal congratulations. The 18th of August was also celebrated throughout the length and breadth of the Monarchy, but only Ischl could claim the presence of the Emperor in person.

Nowadays, the series of celebrations opens with the Kaiserfest on 15 August by the Bürgerkapelle, Bad Ischl's leading musical ensemble. The highlight, however, is the historic and traditional Kaisermesse on 18 August, the Imperial High Mass in the former court parish church of St. Nicholas. Representative companies of the imperial regimental associations attend with their banners and historic uniforms. The service ends with the packed congregation of around one thousand singing the Kaiserhymne to Josef Haydn's famous music, as they did when the young Emperor led his bride to the priest to ask for his blessing, or when he heard it for the very last time in this same church 60 years later, on his 83rd birthday in 1913.

A civic reception by the Mayor of Ischl follows, and there is normally a parade and review of the historic regimental associations at the church, and later in front of the Imperial Villa. There are various secondary events, but for the younger generation in Ischl everything is overshadowed by the Stadtfest, when the town erupts like a volcano throughout the nearest weekend to 18 August, with every section of the local community involved. The festival is the highlight of the entire year in what is still the Kaiserstadt Ischl, where the Habsburg Monarchy remains to this day a conspicuous element in the life of the modern community.

Some pictures of the annual event can be seen online.