In 2004, Cottier told an interviewer: "Going back to the early years, the first “big” text I worked on was the social encyclical Centesimus annus.

And then the Ut unum sint on ecumenicalism, the moral encyclical Veritatis splendor, and the Fides et ratio... also the Catechism of the Catholic Church.

[4][5] After ten years, he exercised his option to become a member of the order of cardinal priests, to which Pope Francis gave his consent on 12 June 2014.

[7] In the run-up to President Barack Obama's 10 July 2009 meeting with Pope Benedict XVI, Cottier praised Obama's “humble realism” in recognizing that the president's "words move in the direction of reducing the evil [of abortion]," and in this manner might align to the thinking of St. Thomas Aquinas and early Christian tradition in terms of framing laws in a pluralistic society.

[8] Cottier reacted to John Paul II's encyclical Ecclesia de Eucharistia by saying that the Catholic Church rejects the concept of open communion.