Stephen Aloysius Leven, third bishop of the Catholic Diocese of San Angelo, one of nine children of Joseph and Gertrude (Conrady) Leven, was born near Blackwell, Oklahoma Territory, on April 30, 1905. He grew up on farms around Ponca City and Newkirk, Oklahoma, where his father was a sharecropper. As a youth Leven received his education at St. Mary's School, Ponca City, and St. Francis Academy, Newkirk. He received an honorary doctorate at St. Edwards University in Austin in 1957. Raised in a devoutly Catholic family, he decided to become a priest at an early age. He was encouraged by his parents and the local pastor and began his studies for the priesthood during high school. He graduated from St. Mary's Seminary, Houston, in 1922 and then entered the American College at the University of Louvain, Belgium. He was ordained a priest for the Diocese of Oklahoma on June 10, 1928, at St. Mary s Church, Ponca City, one of the first native Oklahomans to enter the priesthood. Leven needed a special dispensation to be ordained at the young age of twenty-three. He had learned German as well as English from his German-born parents. In the seminary he mastered Latin. While in Europe he expanded his knowledge of modern languages to include French, Spanish, Italian, and Flemish. His ability in Spanish became especially helpful in his later ministry among Mexicans and people of Mexican ancestry.
Except for three years when he served as vice rector of the American College in Louvain (1935–38), his principal work until his appointment as auxiliary bishop of San Antonio in 1956 was that of parish priest in various Oklahoma parishes. Among his notable activities was the inauguration in 1933 of a "street preaching" ministry based on the work of the Catholic Evidence Guild, which he first saw in London in 1927. During a six-week period that year Leven preached in London's Hyde Park under the direction of the famous lay theologian Frank Ward, later a lifelong friend. As an Oklahoma street preacher, Leven spoke about the beliefs of the Catholic Church in open-air settings, both rural and urban. Courthouse lawns, public parks, vacant lots, and rented halls became places for his pulpit. He propagated accurate knowledge of the Catholic Church in areas where there were few Catholics. During World War II Leven was the official Vatican representative to nine German POW camps in Oklahoma.
On December 7, 1955, Pope Pius XII named Leven titular bishop of Bure and auxiliary to the archbishop of San Antonio. He was consecrated bishop at the Cathedral of Our Lady of Perpetual Help in Oklahoma City on February 6, 1956. As auxiliary to Archbishop Robert E. Lucey of San Antonio, Leven handled many liturgical functions in place of the elderly archbishop, including confirmations and ordinations. He was an auxiliary bishop for thirteen years. Bishop Leven was among 3,000 Catholic bishops from around the world who attended the Second Vatican Council, called by Pope John XXIII. He participated in all four sessions of the council (1962–65) and spoke eloquently on behalf of ecumenical relations, the role of the laity in the church, the relationship of pastor and associate, and other controversial topics.
On October 22, 1969, he was named bishop of San Angelo. He was installed on November 25, 1969, in a ceremony at Sacred Heart Cathedral, San Angelo. In the diocese seventy-eight priests served under him. He had the care of 63,373 Catholics, two-thirds of whom were Mexican or of Mexican descent, over a vast area of west central Texas. During his ten years as bishop of San Angelo, Leven succeeded in solving a number of long-standing financial problems plaguing the diocese. He is credited with making the diocese financially solvent. More than an administrator, he fostered the pastoral care of his people. He encouraged improvements in religious education on the parish level. He also initiated the permanent diaconate program, which trained and ordained more than sixty men to serve as deacons in parishes and missions across the diocese. The first such ordinations took place in 1976 and a second set two years later. He also fostered a strong unity among the priests of the diocese, a difficult task since few were native Texans. In April 1979 illness forced Leven to resign. He retired to Blackwell, Oklahoma, and died there on June 28, 1983. He is buried in San Angelo.