He had a fine physique and his father thus wanted him to pursue a military career, with the intent to eventually appoint him president of the Hofkriegsrat.

In 1792, his father died; from then on, Alexander Leopold served his elder brother who had succeeded as Holy Roman Emperor Francis II.

[4] The same year, Tadeusz Kościuszko, wishing to secure the neutrality of Austria during an uprising against Imperial Russia and the Kingdom of Prussia, offered the crown of Poland to Archduke Alexander Leopold.

[6] Because of his interest in chemistry and especially in pyrotechnics, Archduke Alexander Leopold decided to prepare a firework display at Laxenburg Palace in order to surprise his sister-in-law and cousin, Maria Theresa of Naples and Sicily.

Empress Maria Theresa was on her way to spend summer at the palace, and when her arrival was announced by a gunshot, Alexander Leopold lit the first rocket.