Joseph Gilmore was born in New York City in 1893 to John Joseph and Mary Teresa (née Hanrahan) Gilmore, an ethnic Irish family. When Joseph was five, he moved in 1898 with his family moved to Anaconda, Montana, where his father worked in the mining industry.
He studied at Loras College in Dubuque, Iowa, from where he obtained a Bachelor of Arts degree in 1911.
He served as Bishop of Helena from 1936 until his death in 1962. He continued his studies at the Urban College of Propaganda in Rome, earning a Doctor of Sacred Theology in 1915. While in Rome, Gilmore was ordained to the priesthood on July 25, 1915.
Following his return to Montana, Gilmore served as a professor at Carroll College until 1920, when he became pastor of Saint Teresa"s Church in Whitehall.
He served as pastor of Saint Helena"s Church in Butte from 1925 to 1927. He next served as chancellor of the Diocese of Helena from 1927 to 1936.
On December 9, 1935, Gilmore was appointed the fifth Bishop of Helena by Pope Pius XI. He received his episcopal consecration on February 19, 1936 from Archbishop Amleto Giovanni Cicognani, with Bishops Edwin Vincent O"Hara and Joseph Francis McGrath serving as co-consecrators. During his 26-year-long tenure, he presided over a period of great growth for the diocese.
In addition to the material development, programs were developed to foster vocations, help resettle refugees from World World War II, retrain unskilled workers, aid in adoptions, and promote the lay apostolate.
He was named an Assistant at the Pontifical Throne in 1959. At age 69, Gilmore died unexpectedly in San Francisco, California, while attending the installation of Archbishop Joseph Thomas McGucken.
