Karl Habsburg's career has focused on the issue of protecting cultural heritage from threats such as armed conflict and natural disasters.

[5] At the time of his birth, his father was de facto stateless and possessed a Spanish diplomatic passport (he had grown up in Spain), while his mother was a German citizen.

However, the administrative court of Austria later ruled that applying to return to the country was legal, and his family was granted visa entrance in June 1966.

In 1961, Karl's father, Otto von Habsburg, renounced all claims to the defunct Austrian throne, as a necessary legal condition to being allowed to return to Austria.

[8]Although the Adelsaufhebungsgesetz (Law on the Abolition of the Nobility) abolished all Austrian and Hungarian noble, royal, and imperial titles in 1919,[9] and their usage is still illegal in those countries,[10] media elsewhere occasionally refer to Karl Habsburg by his ancestral titles[11][12] of Archduke of Austria, Royal Prince of Hungary, Bohemia and Croatia.

[13] At the request of the USSR, which was wary of a restoration of the monarchy, the anti-Habsburg laws became mandatory international and constitutional components of the Austrian State Treaty in 1955.

[23] Defunct Karl Habsburg did his military service in 1981 as a platoon commander of a Jäger (infantry) platoon as a one-year volunteer with the Austrian Armed Forces, where he later also completed his pilot training, He is a reserve Hauptmann (captain) in the Austrian Air Force.

[25] In October 1996, Habsburg was elected as a member of the European Parliament (MEP) for Austria, representing the Austrian People's Party.

[30][31][32] After the explosion in the port of Beirut in Lebanon in summer 2020, Habsburg helped coordinate the reconstruction and aid on site.

[3][4] Since 2009, he has been a shareholder in a media group in the Netherlands, consisting of radio stations, a magazine and a music television channel.

[42] The marriage received the dynastic authorization of Karl's father, as head of the House of Habsburg, despite objections from some members of the family as the bride, although a baroness in the nobility of pre-republican Hungary and Transylvania, did not descend in the canonically legitimate male line from a family of dynastic (ruling or formerly ruling or mediatised) status.

After his illness, Karl Habsburg encouraged everyone to follow the official protective measures strictly, and asked survivors of the disease to donate blood plasma.

Also in 1998, evidence emerged that during Habsburg's election campaign for membership in the European Parliament two years prior, his political party the ÖVP, had benefited from at least 30,000 Marks worth of World Vision donations via Paneurope Austria while Karl Habsburg sat on the board of World Vision Austria, apparently without noticing the director's dubiously legal activities.

[52] His father exacerbated the controversy when he complained that his son was being attacked unfairly and drew a parallel between the name "Habsburg" and a yellow badge.