Educated at the Jesuit College in Gorizia, at 16 he tried to reach the island of Crete, where the Venetians were at war with the Ottoman Turks, in order to preach the Gospel and convert the Muslims to Christianity.

On his way, he sought asylum at a Capuchin convent in Capodistria, where he was welcomed by the superior, who knew his family, and who, after providing him with food and rest, advised him to return home.

An impassioned preacher and a skillful mediator, Marco d'Aviano played a crucial role in resolving disputes, restoring unity, and energizing the armies of the Holy League, which included Austria, Poland, and Venice, under the leadership of the Polish king Jan III Sobieski.

[3] From 1683 to 1689, Marco participated in the military campaigns, playing a crucial role in promoting good relations within the Imperial army and encouraging the soldiers.

[3] Notable people who are baptised under protection of Marcus are: In the 2012 Polish and Italian historical drama film The Day of the Siege: September Eleven 1683 about the Battle of Vienna, Marco d'Aviano is portrayed by F. Murray Abraham.

[6] According to legend, after the Battle of Vienna, "the Viennese reportedly found sacks of coffee abandoned by the enemy and, finding it too strong for their taste, diluted it with cream and honey.