Ambassador Donnelly was nominated by President Biden.
The new US ambassador to the Holy See, Joe Donnelly, presented his credentials to Pope Francis at the Vatican's Apostolic Palace on Monday.
Donnelly becomes the 12th US ambassador to the Holy See since diplomatic relations were established between Washington and the Vatican in 1984.
A former senator for Indiana from 2013 to 2019, Donnelly was nominated as US ambassador to the Vatican by President Joe Biden last autumn and his post was confirmed by the senate in January.
In a video statement released by the US embassy to the Holy See, Ambassador Donnelly pledged: "I will do all I can to ensure that the United States and the Vatican work together to advance human rights and dignity.”
“I look forward to deepening our ties with the Holy See" said Donnelly who added: "My family and I are proud to be members of the Catholic faith."
Born in 1955, Donnelly has two children and will be joined in Rome by his wife Jill.
He succeeds Callista Gingrich, who served as US ambassador to the Holy See from December 2017 to January 2021 under President Donald Trump.
Since Biden's inauguration last year, Patrick Connell has served as chargé d’affaires ad interim at the US embassy to the Vatican.
Photo U.S. in Holy See Twitter