[1] During his early years in the diplomatic service of the Holy See, he served in Papua New Guinea, South Korea, the Netherlands, Spain, and Denmark.

He then spent a year in Taiwan as chargé d'affaires and then worked in Rome beginning in late 2002.

On August 17, 2006, Pope Benedict XVI appointed Green as titular archbishop of Altinum, apostolic nuncio to South Africa and Namibia, and apostolic delegate to Botswana.

[1][2] Green was consecrated bishop on September 6, 2006, by Cardinal Secretary of State Angelo Sodano.

[12] Pope Francis accepted his resignation from his posts as nuncio on April 30, 2022.