Bishop Dennis Durning (C.S.S.P) was born on May 18, 1923,[2] in Germantown, Philadelphia, Pennsylvania, United States and died on February 21, 2002, in KCMC hospital, Kilimanjaro, Tanzania.
Dennis Durning graduated the secondary education and decided to join the Congregation of the holy Ghost.
In 1963, Pope John XXIII created the Roman Catholic Diocese of Arusha and appointed Dennis Durning C.S.Sp as his first Bishop on 1 March 1963.
He was succeeded by Bishop Fortunatus Lukanima During his episcopacy, He started with four 4 parishes, one local diocesan priest (The late Fr Simon Sirikwa), 12 Holy Ghost Fathers (Spiritans Missionaries) and 4 Precious Blood Sisters.
After retirement he lived in the parish of the Holy Spirit in the village of Bashai-Lambo, Diocese of Mbulu where continued with missionary service until He died on February 21, 2002, at KCMC Hospital, Moshi, Kilimanjaro.