Son of the Cretan hero Charalambos Tsontos, who was hanged by order of Mustafa Pasha, the Governor of Crete, during the Cretan revolution, he entered the Military School of Evelpidon and as soon as he graduated as an artillery lieutenant (1893), he took part in the Cretan revolution of 1896-1898. He joined the expeditionary corps under Colonel Timoleon Vassos and fought with him. In 1905 he became a lieutenant.
He left with a mission for Macedonia where he replaced the heroic first great fallen tactician Pavlos Mela (1904) on the Western Front. His nickname was Captain Vardas, one of the first organizers of the Macedonian Committee and he was the leader of the corps that operated in the regions of Kastoria, Korestia, Florina and Monastirio (1904-1907). He promoted many Cretan volunteers to Macedonia. Tsontos’ activity was great and the Ottoman authorities put a bounty on his head for 1000 golden Turkish lire. In 1910 he was promoted to captain.
Tsontos then fought in the Balkan wars as a staff major in Divisions I and III (1913). He was proposed by King Constantine I as military commander in the regions of Kilkis, Serres, Drama, Nefrokopi for their cleansing from the Bulgarian komitajis. At the end of the Balkan wars he resigned from the army and left for Northern Epirus where he participated in the movement of the Autonomous Epirus in charge of the Kaza of Korytsa, until October 1914. At the head of a force of 3,000 soldiers he advanced beyond Moschopolis, pushing back the Albanians.
He sided with King Constantine and was discharged from the army. He fled to the mountainous Evritania and Fthiotida where he stayed for three and a half years. With the revolution of 1922 (Plastiras – Gonatas) he retired again until 1926 when he was promoted to Lieutenant General and in 1930 to Lieutenant General in retirement. He became a politician and was elected as a member of parliament three times with the People’s Party. In 1935 he served under the Kondylis government as Minister General of Crete. He left a very rich and important historical record.