Joseph Maximilian Mueller

Joseph Maximilian Mueller (December 1, 1894 – August 9, 1981) was an American prelate of the Roman Catholic Church. He served as Bishop of Sioux City from 1948 to 1970.

Joseph Mueller was born in St. Louis, Missouri, to George Fritz and Barbara (née Ziegler) Mueller. After graduating from SS. Peter and Paul School at St. Louis in 1907, he studied at Pontifical College Josephinum in Columbus, Ohio. He was ordained to the priesthood on June 14, 1919. He then served as a curate in Illinois, serving at Carlyle, Mount Carmel, East St. Louis, and Belleville. He organized and served as the founding pastor of Blessed Sacrament Parish (1926–1930). From 1930 to 1947, he was rector of St. Peter's Cathedral in Belleville. He was named a Domestic Prelate in 1939.

On August 20, 1947, Mueller was appointed Coadjutor Bishop of Sioux City, Iowa, and Titular Bishop of Sinda by Pope Pius XII. He received his episcopal consecration on the following October 16 from Archbishop Amleto Giovanni Cicognani, with Bishops Joseph Henry Leo Schlarman and Edward Joseph Hunkeler serving as co-consecrators. Upon the death of Bishop Edmond Heelan, Mueller succeeded him as the third Bishop of Sioux City on September 20, 1948. During his 22-year-long tenure, he presided over a period of great expansion in the diocese. He built several new schools, churches, and other parish facilities. He also attended all four sessions of the Second Vatican Council between 1962 and 1965.

After reaching the mandatory retirement age of 75, Mueller resigned as Bishop of Sioux City on October 20, 1970; he was appointed Titular Bishop of Simitthu by Pope Paul VI on the same date. He resigned his titular see on January 13, 1971. He later died at age 86.