Thomas Hennen was born on July 4, 1978, in Ottumwa, Iowa, to (the late) John and Jo'An Hennen. He is the youngest of 11 children.[1] He received a bachelor's degree in history and philosophy from St. Ambrose University in Davenport, Iowa.[2] Hennen went to Rome to continue his studies while residing at the Pontifical North American College. He earned a Bachelor of Sacred Theology degree from the Pontifical Gregorian University in 2003.
Hennen was ordained a priest at Sacred Heart Cathedral in Davenport by Bishop William Franklin for the Diocese of Davenport on July 10, 2004.[1] He earned a Licentiate of Sacred Theology in 2005 from the Pontifical Alphonsian Academy in Rome.
After his return from Rome, the diocese assigned Hennen in 2005 as parochial vicar at Prince of Peace Parish in Clinton, Iowa. He was reassigned in 2010 as a campus minister and as parochial vicar of St. Mary's Parish in Iowa City. After one year, the diocese named Hennen as its director of vocations. He was also appointed in 2014 as chaplain and theology teacher at Assumption High School in Davenport. In 2015, Hennen was moved from St. Mary's to Sacred Heart Parish in Oxford Junction, St. James Parish in Toronto, Sacred Heart Parish in Lost Nation and Saints Philip and James Parish in Grand Mound, all in Iowa.
Hennen left his existing positions in 2017 to serve as chaplain and director of campus ministry at St. Ambrose University and parochial vicar at St. Anthony's Parish in Davenport. He was named a diocesan consultor and the vicar general in 2020. From 2021 to 2025, Hennen served as priest moderator of St. Andrew Parish in Blue Grass, Iowa, and pastor and rector of Sacred Heart Cathedral.[2]
In addition to his pastoral and administrative assignments, Hennen served on a committee established by Bishop Thomas Zinkula that drafted a diocesan policy regarding sexual and gender identity issues.[1] Beginning in January 2023, he wrote the Question Box column for the diocesan paper, The Catholic Messenger.[3]
On July 10, 2025, Pope Leo XIV named Hennen the seventh bishop of Baker.[1][2] He was ordained and installed by Archbishop Alexander Sample of Portland in Oregon on September 29, 2025, at St. Francis of Assisi Church in Bend, Oregon.[4] Bishop Emeritus Liam Cary of Baker and Bishop Dennis Walsh of Davenport served as the principal co-consecrators.[5] Upon his ordination, Hennen is the youngest sitting American Catholic bishop.[3]
