He was director of a special programme focussing on human development and gave a general introduction to first year students on prayer, scripture and the Church.

In his 1991 First Year Moderators Report, Dew expressed a real sense of frustration at the unsuitability of many students.

Dew urged that in the future, diocesan vocations directors pay particular attention to eight issues with evaluating prospective students: basic knowledge of the Catholic faith; familiarity with meditation, prayer and the scriptures; a reasonable comfort with affectivity; personal independence; social comfort; intellectual curiosity; generosity; and a genuine desire and free decision to enter the seminary.

"[6] Because Sacred Heart Cathedral would not have held the expected congregation, he was consecrated bishop in the Wellington Town Hall which was filled to capacity.

[4] Dew attended the Synod of Bishops on "The Eucharist: Source and Summit of the Life and Mission of the Church" in October 2005 (see below).

[10] Pope Francis accepted Dew's resignation on his 75th birthday, 5 May 2023 on which date he was succeeded by Paul Martin, his coadjutor archbishop.

[13] On 14 February 2015, Pope Francis made Dew a member of the College of Cardinals with the title of Cardinal-Priest of Sant'Ippolito.

[18][19] He became the fourth New Zealand cardinal, joining Thomas Williams, who was no longer eligible to participate in a papal conclave.

"[21] On 13 April 2015, Dew was appointed a member of the Congregation for the Evangelization of Peoples and of the Pontifical Council for Promoting Christian Unity.

[22] He participated in the Fourteenth Ordinary General Assembly of the Synod of Bishops (4–25 October 2015) on "The vocation and mission of the family in the Church and in the contemporary world".

"[9][25] After this 2005 speech, Dew discussed the issue with Cardinal Jorge Mario Bergoglio, the future Pope Francis.

"[27] In February 2015, Dew said he and Soane Patita Paini Mafi of Tonga, who was soon to become a cardinal alongside him, wanted to highlight two issues: the effect of climate change on the countries of the South Pacific and the problem of human trafficking in that part of the world.

"[29] On 26 March 2021, Cardinal John Dew, the Archbishop of Wellington and president of New Zealand Catholic Bishops Conference, apologized to abuse victims in the Royal Commission of Inquiry and stated that its systems and culture must change.

The alleged victims were aged 7 and 8 in November 1977 when the assaults are said to have occurred at St Joseph's Orphanage in Upper Hutt.

[34] The survivors' support network SNAP Aotearoa New Zealand accused Dew of hypocrisy after he attempted to conceal the allegations against him.