Satowaki was born in Shitsu, and studied at the seminary of Nagasaki, Pontifical Urbaniana University in Rome, and Catholic University of America in Washington, D.C.[1] As a seminarian in Rome, he invited the Polish Conventual Franciscan friar and future saint Maximilian Kolbe to come to Japan as a missionary.

[2] Ordained to the priesthood on December 17, 1932,[3] he did pastoral work in the Diocese of Nagasaki and served as procurator and episcopal chancellor.

Between 1945 and 1955, he served as vicar general, editor of diocesan newspaper, and a teacher at the Junshin School.

[3] He received his episcopal consecration on the following May 3 from Archbishop Maximilien de Furstenberg, with Bishops Paul Aijirô Yamaguchi and Paul Yoshigoro Taguchi serving as co-consecrators, at the church of Our Lady of the Martyrs in Nagasaki.

[1] Pope John Paul II created him Cardinal Priest of S. Maria della Pace in the consistory of June 30, 1979.