William Joensen was born on July 8, 1960, in Waterloo, Iowa to Alfred W. Joensen and Marilyn E. (née Simington) Joensen. He is the eldest of five children and grew up in Ames, Iowa.[1] Joensen received a Bachelor of Science degree in zoology from Iowa State University in Ames, Iowa. He was attending medical school at the University of Iowa in Iowa City, Iowa, when he decided instead to study for the priesthood. Joensen's seminary education was at the Pontifical College Josephinum in Columbus, Ohio.[2][3]
After his 1989 ordination, the archdiocese assigned him as associate pastor of Sacred Heart Parish in Waterloo and faculty member of Columbus High School in Waterloo. He left these two posts in 1992 to become associate pastor of the Church of the Resurrection Parish in Dubuque.[5] Joensen in 1995 went to Washington D.C. to attend the Catholic University of America, where he earned a Doctor of Philosophy degree in 2001.[6][3]
When Joensen returned to Iowa, he served as a chaplain at Clarke College in Dubuque from 2003 to 2010. At Loras College in Dubuque, Joensen served as chaplain, associate professor of philosophy, and dean of campus spiritual life. At Dubuque's St. Pius X Seminary Joensen was the spiritual director. Joensen also served as a faculty member at the Tertio Millennio Seminar on the Free Society in Kraków, Poland.[6][2]
In January 2023, Joensen published a decree that required students in Catholic schools to dress according to their gender at birth and use bathrooms and locker rooms accordingly.[8]