Joseph Penkaul enlisted in the Army in 1958, and upon being discharged in 1961 attended St. John Vianney Seminary in East Aurora, New York, and Niagara University, Niagara Falls, New York. He was subsequently commissioned as a Chaplain in the Army Reserve in 1970, and transferred to the Air Force Reserve in 1973. He retired in 1996 as a U.S. Air Force Brigadier General.