[4] Pope Pius IX in 1850 erected the Vicariate Apostolic of Indian Territory East of the Rocky Mountains.

This huge jurisdiction contained the present-day states of Kansas, Nebraska, North and South Dakota, Colorado, Wyoming, and Montana.

[8] In 1855, Miège established his episcopal see in Leavenworth, Kansas, in order to better minister to the growing number of Catholic European settlers there.

[7] In 1871, Pius IX named Reverend Louis Fink as coadjutor vicar apostolic to assist Miège with his duties.

[13] At the beginning of Fink's tenure in 1874, the vicariate contained 65 priests, 88 churches, 13 parochial schools, and a Catholic population of approximately 25,000.

By the time of Fink's death in 1904, the Diocese of Leavenworth had 110 priests, 100 churches, 13 stations and chapels, 37 parochial schools, and 35,000 Catholics.

[14] The second bishop of Leavenworth was Monsignor Thomas Lillis from Kansas City, Missouri, named by Pope Pius X in 1904.

In 1927, Reverend Francis Johannes from the Diocese of St. Joseph was appointed coadjutor bishop in Leavenworth by Pope Pius XI to assist Ward.

[18] In 1990, Strecker established background and reference checks for all persons working with children, including employees and volunteers, at the archdiocese as part of a policy to combat sexual abuse of minors.

[21] In 1996, Keleher started an education program to fight child sexual abuse in the archdiocese and instituted a background questionnaire for anyone working with children.

Keleher established an independent review board in 2002 to investigate and issue recommendations on all allegations of sexual abuse.

[22] In January 2004, John Paul II appointed Auxiliary Bishop Joseph Naumann of St. Louis to serve as coadjutor archbishop for Keleher.

[23] In February 2004, Keleher requested that the parishes and Catholic institutions within the archdiocese stop inviting politicians who support abortion rights for women to any events.

Naumann stated that he tried to persuade Sebelius to change her stand on abortion rights, and after her refusal in doing so, he denied her communion.

[25] The archdiocese in 2022 spent $2.45 million in support of an ill-fated proposed amendment to the Kansas constitution to remove its protection of abortion rights, which was defeated by a 59 to 41% margin.