He was a member of the Congregatio Immaculati Cordis Mariae (CICM; Congregation of the Immaculate Heart of Mary) missionary order, and proselyted in China in the 1930s, then later became a professor of Chinese at the University of Washington.

[1] The school required students to become fluent in French and German, as well as in the Latin and Greek Classics, which stimulated Serruys' interest in linguistics and philology.

[1] In 1930, after he completed secondary school, Serruys followed his older brother Henry in joining the novitiate of the Congregatio Immaculati Cordis Mariae (Congregation of the Immaculate Heart of Mary), a Roman Catholic missionary order focused on East Asia and Africa.

[2] Serruys arrived in Tianjin in November 1937 after a difficult two-month sea voyage, then traveled by train to his assigned parish in Xicetian (西册田), a small village in Shanxi Province located between Datong city and Hunyuan County along the banks of the Sanggan River.

[2] At the time, the area was occupied by the Imperial Japanese Army, while the countryside was patrolled by Chinese guerrilla fighters and bandits, making travel often dangerous.

Serruys' focus on studying the local language was often criticized by other missionaries, who felt he cared more about linguistic research than ministering to his congregants and proselytizing.

[6] Early in his time at Washington, Serruys focused his research on Chinese bronze inscriptions, but later became engrossed in the study of oracle bone script.

[6] His research culminated in his article "Studies in the Language of the Shang Oracle Inscriptions", published in T'oung Pao in 1974, which is considered "a cornerstone of [the] field" among Western scholars.

The order provided space for Serruys' large book collection, and he spent the last years of his life doing as much research and correspondence as his health allowed.