Fr. Appel spent his childhood in Ottumwa, and then graduated from St. Ambrose University. He then completed theology studies at the University of St. Mary of the Lake Seminary in Mundelein, Illinois, followed by canon law studies at Catholic University of America.
His ordination to the priesthood was in 2003, with his first appointment as parochial vicar at St. Paul the Apostle in Davenport. This was followed by appointments at Our Lady of Victory in Davenport, Ss. Mary & Mathias in Muscatine, St. Joseph in Columbus Junction, and St. James in Washington.
After pursuing advanced studies, he returned to serve two parishes, St. Alphonsus in Davenport and St. Peter in Buffalo. Father Paul Appel also serves the Diocese of Davenport as judicial vicar, vice chancellor, and delegate for the Bishop in matrimonial matters.