Kevenhoerster was born at Essen in North Rhine-Westphalia.[1] At age 11, he immigrated with his family to the United States, where they settled in Minneapolis, Minnesota.[2] After receiving his early education at public and parochial schools, he studied at St. John's College and the University of Minnesota.[1] He entered the Order of Saint Benedict, more commonly known as the Benedictines, at St. John's Abbey in Collegeville, and made his profession on July 25, 1892.[3] He then served as the assistant to the master of novices at St. John's.[4]
He was ordained to the priesthood on June 24, 1896.[3] He then served as a professor, as well as a chaplain and moderator of the Alexian Literary Society, at St. John's College.[4] He later became rector of the college and prior of the abbey.[1] From 1907 to 1929, he was pastor of St. Anselm's Church in the Bronx borough of New York City.[2] He then served as vicar forane of the Bahama Islands, as well as superior of the Benedictines there, from 1929 to 1931.[1] During this time, he worked as a chaplain at prisons and hospitals, and taught classes to Catholic converts.[4]
On May 22, 1931, Kevenhoerster was appointed the first Prefect Apostolic of the newly created Prefecture Apostolic of the Bahama Islands by Pope Pius XI.[3] Each year he made a begging trip to the United States to collect funds to be used in the building of parochial schools.[4] On October 27, 1933, he was named to succeed the late Bishop John Dunn as titular bishop of Camuliana.[3] He received his episcopal consecration on the following December 21 from Cardinal Patrick Hayes, with Archbishop John Murray and Bishop Joseph Busch serving as co-consecrators, at St. Patrick's Cathedral in New York.[3]
Kevenhoerster was formally enthroned by Cardinal Hayes in Nassau on February 4, 1934.[5] At the ceremony, Hayes commented, "New York's loss is the Bahamas' gain."[5] Later that same year, he returned to New York to ask for financial aid for the Bahamas to complete the rebuilding of two churches destroyed by a hurricane.[6] In 1940, he attended the annual Catholic Mission Sunday at St. Patrick's Cathedral, where he occupied the seat of honor opposite the Archbishop's throne.[6]
On January 15, 1941, the Prefecture Apostolic was elevated to the Vicariate Apostolic of the Bahama Islands, with Kevenhoerster becoming its first Vicar Apostolic.[3] He spent a total of twenty years in the Bahamas and, during his tenure, the islands' Catholic population rose from 3,200 (1929) to 13,054 (1954).[4] He also established several convents and a congregation of nuns, founded St. Augustine's Monastery and College in Nassau, and encouraged the creation of Boy Scouts and Clubs in churches.[4] In June 1946, he was named an Assistant at the Pontifical Throne by Pope Pius XII on the occasion of the golden jubilee of his priestly ordination.[6]
Kevenhoerster experienced fragile health and suffered several strokes in his final years.[4] He died in Nassau at age 80.[6]