Biographical data
He was born October 26, 1897 in Sinope on the Black Sea and was the son of Eleftherios and Catherine Vaportzis. His uncle was Metropolitan Kirillos Mumtzis of Mytilene. After completing his studies in his homeland, he enrolled in the School of Theology in Halki, graduating after a year's hiatus due to World War I in 1919 with his thesis "The Election of the Patriarchs of Constantinople in the Byzantine Era." He was ordained a deacon on May 16, 1918, and an elder on New Year's Day 1928, receiving the title of archimandrite at the same time.

High Priest
On February 8, 1930, he was elected Metropolitan of Philadelphia, and on June 28, 1932, he was elected Metropolitan of Chalcedon.

After the death of Patriarch Photios II in 1935, the preferred successor was Maximos, but after the intervention of the Turkish authorities, his name was removed from the list of candidates. During World War II he was arrested twice by Turkish authorities, and the second time (January 20, 1943) he was deported to Prussia for several months.

Due to Patriarch Benjamin's advanced age, Maximos replaced him in many administrative tasks and was a permanent member of the Patriarchal Synod.

Patriarch
In February 1946, he died Patriarch Benjamin. The day after his funeral, on February 20, Maximin was elected Ecumenical Patriarch by the Patriarchal Synod. It is noteworthy that the Turkish government maintained a neutral position, not creating obstacles to his election, as it had location previous time. It seemed, moreover, that the climate between the Turkish authorities and the Patriarchate had changed. An indicator of the improvement in the situation at the time was the visit of the then President of the Turkish Republic Ismet Inonu to the Halki School of Theology, where he was warmly received by the then director, Metropolitan Chrysostomos of Neocaesarea, and the students.

From the very first months of his patriarchate, Maximos was already pulling his weight fire Turkish press because of its contacts with the Russian Orthodox Church, which were interpreted as indirect support for the Soviet Union. American and British diplomats seem to have had similar suspicions. It seems that he did not fully understand the change in relations after the war, and his ill-advised statements left room for interpretation as pro-Russian.

Disease
Toward the end of 1946, the Patriarch began to show symptoms of mild melancholy. After a while, the Patriarch expressed his intention to resign, while information leaked out from Turkish circles that if he was diagnosed with a terminal illness, he should be immediately remove and choose a successor. The Greek Foreign Ministry was informed by Greek Ambassador Pericles Skeferis of the patriarch's intentions, and the Greek government recommended waiting.

In order to recover, it was decided to move the patriarch to his summer residence in Halki and then, in May 1947, to Athens. Thus, accompanied by three members of his entourage, he arrived by train from Sikertzi station in Pythio on Evros, from where he was taken by motorcade to Alexandroupolis, where he was received by the bishops of Fthiotida Ambrosios and Attica and Megaridos Iakovos, representing the Church Greece. He and his entourage then boarded the Greek destroyer "Crete" bound for Piraeus, where he set sail at 1:30 p.m. on May 21, 1947, amid the frenzy of flag raising, the hiss of docked ships, the joyous ringing of bells and the cheers of Piraeus residents gathered around the port. There he was received by Alexander Papagos, Archbishop of Damascene, the Cabinet, etc. and then went to Kifissia, where he settled. The treatment that followed is characterized as cursory and disorganized, and from this it is inferred that the Greek government was probably more interested in convincing the patriarch to resign than in his recovery.

Despite strong rumors of his resignation while being treated in Athens, Patriarch Maximos returned to Constantinople in August of that year without deciding to resign.

Processes
The Patriarch's prolonged illness and intense speculation about his successor created a climate of conflict in Phanar. The Greek government, in consultation with the U.S. government, continued the search for a new "strong personality" with a clear "anti-Russian" orientation who could transform the Patriarchate into an "anti-communist bastion," traits also in line with Turkey's policy. In the end, the Greek government opted for Athenagoras' candidacy, which in time won the support of both the hierarchy and foreign governments. Ankara and the Turkish press supported Athenagoras' proposal, even describing him as a "faithful friend of Turkey."

However, the reactions of the patriarchate's metropolitans, once the moves of the aforementioned governments became known, were strong. At the forefront of the reacting hierarchs, who recognized the external manipulation of the Patriarchate, were the Metropolitans of Derki Joachim, Laodicea Maximos, Neocaesarea Chrysostomos, Pergamum Adamantios, Sardei Maximos and Chaldia Kirillos, who responded to comments made by Athens representatives about the need to replace the Patriarch, due to illness, by defending the Patriarchate's independence, repliedthat many times in its long history the Patriarchate has faced similar situations, which it has managed to overcome on its own, so there is no need for external factors to influence internal arrangements.

At the same time, pressure from the Greek government and circles in Phanar continued unabated for Maximos to step down. In 1948, presumably to fend off accusations of Russophilia, he refused to affiliate the Czechoslovak Church to the Moscow Patriarchate, as requested by Archbishop Savatius of Prague.

Resignation and death
He finally resigned on October 18, 1948, after the Greek and Turkish governments voted in favor of Athenagoras' election to the patriarchal throne. It is claimed that his illness was a pretext for forcing his resignation, and the real reason was rumors of his ties to the Russian Church and thus to the Soviet Union.

He retained the title of president of Ephesus, given to him by the Patriarchal Council. In 1971 he fell ill with acute bronchitis and died in Switzerland on New Year's Day 1972. His body was taken to Constantinople, where he was buried with honors in the courtyard of the patriarchal monastery of Zoodochos Pigi Baluklis.

In a letter dated 25/5/1962 (which was later published in the Orthodox Press (Vol. 191-192, Aug. 1 & 15, 1973)), the dethroned Maximos V accused Athenagoras of the deceit with which he deposed him, especially his ecumenical overtures.