Drennan was appointed coadjutor bishop of Palmerston North by Pope Benedict XVI on 22 February 2011. He chose as his motto
caritas congaudet veritati (love delights in the truth), taken from the
First Letter of St Paul to the Corinthians, chapter 13. His principal consecrator was his future predecessor, Bishop Peter Cullinane of Palmerston North and the principal co-consecrators were Bishop
Barry Jones of
Christchurch and Archbishop
Mark Coleridge of
Canberra-Goulburn. Drennan succeeded to the
see on 22 February 2012, upon the retirement of Peter Cullinane. His installation took place at the Cathedral of the Holy Spirit on 17 March 2012. On 7 March 2015, Drennan joined with other protestors in a
demonstration in Palmerston North in relation to the
Trans-Pacific Partnership (TPP). In a speech to the 500 protestors in
The square, he said: "Absolute freedom is not in our interests." "It most certainly is not a right of global business interests to trump the duty of an elected government to govern a nation's economy in accord with the wishes of that nation's citizens." Drennan also denounced the secrecy of the TPP negotiations. Drennan was a member of the executive committee of the Federation of Catholic Bishops Conferences of Oceania and a bishop member of the board of the New Zealand Catholic Education Office Ltd. He served as a member of the New Zealand Catholic Bishops Conference Commission until his resignation in October 2019. ==References==