Sergey Grigoryevich Chavain was born in 1888 into a poor peasant family. His father, Grigory Mikhailov, was a peasant and tar maker, while his mother, Tatyana Anisimovna, had a talent for storytelling and knew many folk tales and songs, which she passed on to her son.

In 1908, he graduated from the Kazan Teacher's Seminary and taught in Mari schools until 1915. In 1915, Chavain moved to Aralsk, Kazakhstan, where he worked as a teacher in a settlement near the railway station until 1919, avoiding conscription into the tsarist army and participation in the war.

Upon returning home in 1919, he played an important role in the creation of the autonomy of the Mari people and headed the regional political education department. In 1922 and 1923, he began working for the newspaper 'Yoshkar Kec' and later became its editor-in-chief. In 1923, he returned to teaching, managing a school in the village of Arino in the Morkinsky district.

In 1927, Chavain returned to journalism, moved to Yoshkar-Ola, and worked at the Mari Book Publishing House. In 1934, he became one of the first Mari writers accepted into the Union of Soviet Writers. He was the organizer of the Mari Association of Proletarian Writers and a member of the board of the Mari regional branch of the Union of Writers of the USSR, as well as the board of the writers' organization of the Gorky region.

Chavain taught at the Mari Studio of Musical and Dramatic Arts and managed the literary department of the Mari State Theater. In May 1937, he was arrested on charges of participating in an underground nationalist organization and preparing terrorist acts against the country's leadership. On November 11, 1937, he was executed and is believed to have been buried in the Kokshai Forest, now the Mendurskoye Cemetery. He was posthumously rehabilitated in 1956.

While studying at the Kazan Teacher's Seminary, Sergey Grigoryevich adopted the literary pseudonym Chavain. Mordovian literary scholar N. I. Cherapkin notes in his book 'Tributaries' that this pseudonym signifies belonging to the lineage of Chavay, a legendary Mari hero of the 16th century.