 On May 30, 2008, Jackels served as a co-consecrator to Auxiliary Bishop James D. Conley of Denver, Colorado, who was a priest of the diocese of Wichita prior to his appointment on April 10, 2008.Bishop Jackels joins young Catholics in the annual "March for Life" in Washington, D.C.

On April 8, 2013, Pope Francis appointed Jackels archbishop of the Archdiocese of Dubuque.He was installed by Archbishop Carlo Maria Vigano, Apostolic Nuncio to the United States, on May 30, 2013 at the Church of the Nativity in Dubuque.