Pierre then held posts in Mozambique, Zimbabwe, Cuba, Brazil, and as the Permanent Observer of the Holy See to the United Nations in Geneva.

On 12 July 1995, Pope John Paul II named Pierre as apostolic nuncio to Haiti and titular archbishop of Gunela.

[2] Vice President Speciosa Kazibwe, herself a doctor, promoted condom use during a national tour and complained that religious leaders were hampering the government's public health efforts.

[4] During his time in Uganda, Pierre worked with Italian missionary Father John Scalabrini in supporting many disadvantaged Ugandans with school and health care.

[8] Jorge E. Traslosheros wrote in Crux that, while in Mexico, Pierre managed "to weave with an artist's skills unity among Catholics, thereby overcoming the political divisions and culture wars that have caused so much damage".

[9] Pope Francis named Pierre apostolic nuncio to the United States on 12 April 2016, succeeding Archbishop Carlo Maria Viganò.

[10] Advocating for immigrants, he joined demonstrations and meetings with Texas-Mexico border bishops in October 2016 in Nogales, Arizona,[11] and in February 2016 in San Juan, Puerto Rico.