Though he is happy to be back in active ministry, the archbishop said his time in the Vatican was "a real grace," especially in serving under three Popes.
Having arrived toward the end of St. John Paul II's pontificate, Archbishop Wells said he was amazed to see that the Polish Pope was "still so active, still so engaged with his limitations."
Benedict XVI, with whom the Archbishop frequently traveled, including during his 2008 visit to the United States, "was such a humble, incredibly humble person," he said.
While many thought the German pontiff was timid, Archbishop Wells said he didn't see him that way.
"I never thought he was timid…he's humble and incredibly respectful. And because of the respect, maybe as a professor…he always showed incredible respect for the other person, but he wanted to let them express their ideas, their views, and then he would say something."
Francis, on the other hand, has been "a whirlwind since day one," the archbishop said, chuckling.
He said that though the Argentine has only been in office for three years, "it's been an extremely invigorating time and a very beautiful time, especially to see how Pope Francis has this ability to touch everyone's heart immediately."
Touching on the differences in the diplomatic tone of each of the Popes under whom he's served, Archbishop Well said that St. John Paul II "was extraordinary" in terms of his diplomatic service.
"(John Paul) interacted on the entire world stage and was very much a part of the fall of the Eastern Bloc," he said, crediting the saint's input, diplomatic tact, and rapport with other heads of state in helping to eliminate communism in Europe.
The archbishop said that in his opinion, one of the most significant contributions of Benedict XVI in the diplomatic world was that he continuously talked about "the importance of the relationship between faith and reason," as well as the importance of religious communities in having a voice in the public forum.
Francis has followed closely in his predecessors' footsteps, and has already had a huge impact in just three years, Archbishop Wells said, pointing specifically to Francis' role in helping to restore U.S.-Cuba relations and in drawing attention to the global migrant crisis.
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"He has a keen sense of what is happening, but he never, ever loses the idea that it's the human person who is at the center," he said, adding that "we can never lose the concept of the integral and core nature of the human person."
The archbishop said that one of the biggest challenges in his tenure has been not only his assistance in streamlining Vatican communications – he is one of the officials who pushed for the Pope's Twitter account – but also knowing how to deal with Benedict XVI's resignation.
"We didn't have instruments, or really archives, of how to deal with the resignation of the Pope and how to move forward in the interim, so we had to come up with new models of dealing with things."
A large part of the discussion centered on determining what would happen when Benedict actually resigned, he said.
In order to signify that he had actually stepped down, they finally agreed to close the doors to Castel Gandolfo and to remove the Swiss Guard (the personal protectors of the Holy Father), replacing them with the Gendarme, the Vatican's police service.
"Our communications office did a beautiful job following Pope Benedict in the helicopter, and the way that that was shown to the world was extraordinary," he said. "Everyone could really participate in what was happening, because it was a historical moment."