His parents were Károly Derecskei and Erzsébet Heim; he had two siblings. He studied law and served as a district judge; he performed military service during World War I, was taken prisoner of war, and returned to his homeland via Vladivostok in 1921. He completed his novitiate in Érd from 1923 to 1925, then studied philosophy in Jersey from 1926 to 1927. In 1929, he spent his master’s degree years in Kalocsa, then completed his philosophy studies in Szeged, after which he studied theology. He was ordained a priest on July 1, 1933. In 1935, he was sent to Ankara for the Turkish mission; in the meantime, he returned to Szeged in 1937, where he completed his tertianship. From 1938, he ministered to Hungarians in Istanbul, and from 1939 to 1954, he served as a Hungarian pastor in Ankara. He lived in the United States from 1955 onward. He passed away at the age of 102.

Rev. Derecskei János jezsuita atya. Önéletrajz. London (ON, Kanada), 1983; Élettörténetem. MJV II. 157–76.