Parhon was President of the Physicians and Naturalists Society in Iași, director of medical institutes, professor, and a titular member of the Romanian Academy.

[4] A short while after the fusion, Parhon split with the group and became politically inclined toward the Romanian Communist Party.

[5] In November 1944, after the August 23 coup d'état that led Romania to switch sides in the war and join the Allies, he became President of the Romanian Association for Strengthening the Ties with the Soviet Union, which had been founded at his villa in Sinaia.

The same law provided for a Presidium composed of five members (elected by the Deputies' Assembly) to exercise the executive powers in the state; alongside Parhon, its members were Mihail Sadoveanu, Ștefan Voitec, Gheorghe Stere [ro], and Ion Niculi.

On 13 April 1948, the Parliament adopted a new Constitution, which borrowed heavily from the Soviet model of 1936[6] and entrusted the supreme powers to the Great National Assembly – which in turn elected a Presidium, composed of a president, three vice-presidents, a secretary and 14 members.

The same day, Parhon was elected as President of the Presidium, though the real power in the state was exercised by the Romanian Workers' Party and its First Secretary, Gheorghe Gheorgiu-Dej.

He was buried in the round hall of The Monument of the Heroes for the Freedom of the People and of the Motherland, for Socialism in Bucharest's Carol Park.

Streets in Bârlad, Cornățelu, Mangalia, Mediaș, and Râmnicu Sărat are named in his honor, as is the Dr. C. I. Parhon Hospital in Iași.