Otto was a son of Archduke Karl Ludwig of Austria and his wife, Princess Maria Annunciata of Bourbon-Two Sicilies. Otto's father, Karl Ludwig, was a younger brother of Emperor Franz Joseph I of Austria; and Karl Ludwig became heir presumptive to the Austro-Hungarian throne when his nephew Crown Prince Rudolf committed suicide in 1889. Although a newspaper account claimed that Karl Ludwig renounced his rights to the throne that same year (1889) in favour of his eldest son, Franz Ferdinand, that story is not certain.