Archduke Johann Salvator was born in Florence, the youngest son of Leopold II, Grand Duke of Tuscany and his second wife, Princess Maria Antonia of the Two Sicilies.

[1] He pursued a career in the Austrian Army and was a good friend of Rudolf, Crown Prince of Austria, with both sharing liberal opinions.

During the Austro-Hungarian occupation of Ottoman Bosnia and Herzegovina in 1878, he was put in command of a division of the occupying army and won numerous honours.

[4][5] On 16 October 1889, he resigned his army commission and renounced his title and the privileges he enjoyed as a member of the Austrian imperial family.

[7] Shortly after his marriage, he purchased a ship named the Santa Margareta, on which he and his wife sailed for South America.