In 1817, he joined the "Filiki Eteria" secret society and returned to his homeland, recruiting others in preparation for an anti–Ottoman revolt. In 1821, with the start of the Greek War of Independence against the Ottoman Empire he led the Greek insurgents in Magnesia. After the suppression of the revolt there, he went to Central Greece. He represented Magnesia in National Assemblies of Epidaurus and Astros and worked in commissions regarding military affairs and education. In 1827, he fell ill and his condition steadily deteriorated until his death on 24 June 1828 in Ermoupoli, Syros. Gazis died in poverty, having donated most of his savings to the Greek army.