As of 2023, the diocese had 57 parishes and 38 missions divided into six deaneries: Bozeman, Butte, Conrad, Helena, Kalispell, and Missoula.

[8] Brondel took a particular interest in the evangelization of Native Americans, and the United States government often used his popularity among that community to further its aims.

[11] After Brondel died in 1903, the next bishop of Helena was Reverend John Carroll of the Diocese of Dubuque, named by Pope Pius X.

[14] Carroll was a vocal opponent of socialism, which he believed made "no allowance for the development of man's talents, intellectual gifts, his spirit of economy or his ability.

"[15] He also condemned alcohol as "the most prolific source of poverty and misery"[16] and successfully lobbied the Helena City Council to require bars to close by midnight.

[20] Finnigan worked hard to gain accreditation and long-term financial support for Mount St. Charles College.

In 1933, Pope Pius XI appointed Reverend Ralph Hayes from the Diocese of Pittsburgh as the fourth bishop of Helena.

[22] After Gilmore died in 1969, Pope Paul VI named Monsignor Raymond Hunthausen of Helena as the next bishop of the diocese.

[23] Starting in 1976, Hunthausen worked with Call to Action, a progressive Catholic group, and sought to implement their program.

His tenure as bishop of Helena was marked by increased lay involvement in church matters, the establishment of a mission in Guatemala, the closure of several Catholic elementary and high schools, and the strengthening of religious education programs.

Pope John Paul II appointed Monsignor Alexander Brunett of the Archdiocese of Detroit to replace Curtiss.

[25] Shortly after his arrival in Helena, Brunett began touring the diocese, attending welcoming ceremonies and visiting parishes.

He regularly visited local Indian reservations, and was initiated into the Blackfeet Nation, receiving the name "Holy Eagle Feather".

Monsignor Robert C. Morlino of the Diocese of Kalamazoo was named bishop of Helena by John Paul II in 1999.

On January 31, 2014, the diocese filed for Chapter 11 bankruptcy protection as part of a $15 million settlement intended to go to 362 victims of sex abuse by clergy.