[2] He received his early education at the local cathedral school and the Christian Brothers College in Town and Country, Missouri, graduating there in 1862.

[1] Hennessy then served as pastor of a parish in Iron Mountain, Missouri, with his jurisdiction extending as far south as Arkansas.

[1] Hennessy established the Catholic Railroad Men's Benevolent Union in 1871, a convent for the Ursuline Sisters at Arcadia in 1877, and the first total abstinence society in southeast Missouri.

[3] In 1890, Hennessy persuaded the Sisters of the Sorrowful Mother to come to the United States and take over management of St. Francis Hospital in Wichita.

[6] He broke ground for the Cathedral of the Immaculate Conception in Wichita in April 1906 and laid the cornerstone the following October; it was dedicated by Cardinal James Gibbons in September 1912.