"Few had predicted that it would be this humble and modest person," writes Arborelius in a statement on the Catholic Church's website.
"Many reacted to the fact that we got a pope for the first time. At the same time, he has lived and worked more in Peru than in his home country. His family has an immigrant background, just like his birthplace Chicago."
He also seems to give a jab to the US President Donald Trump, in a comparison with Prevost.
"It's hard to imagine anyone who, by their nature, is more unlike him than another American who has made a spectacle of himself to become pope," says Arborelius.
He adds that Leo XIV "with his gentle demeanor can succeed in conveying the gospel's message of peace and reconciliation to the world's powerful."
Anders Arborelius is the first Swede ever to participate in the conclave's top-secret work of electing a new pope.
Cardinal is the second-highest position within the Catholic Church after the pope, and cardinals retain their title for life.
