Poli, 66, is a priest very much in Francis' vein, focused on pastoral work, and he made news recently when he publicly dressed-down a priest who had posted a Facebook greeting on the birthday of former Argentine dictator Jorge Videla.
Poli has been the bishop in Santa Rosa in the rural La Pampa province, and from 2002-2008 he served as one of Cardinal Jorge Mario Bergoglio's auxiliary bishops in the Argentine capital, but he was not among the church officials rumoured to be top candidates for the post.
"It's no longer like it was. In the seminary, older people are coming in. This is a much better situation, because in the UBA you become acquainted with real life, the different points of view there are about it, the different scientific aspects, cosmopolitanism," Bergoglio said. "It's a way of having your feet well planted in the earth."
Poli was involved in the church's failed effort to prevent Argentina from becoming the first Latin American country to legalize gay marriage in 2010, writing lawmakers an open letter urging them to vote against it.
Poli also wrote a firm response after a priest in one of his parishes, Jorge Luis Hidalgo, posted a Facebook message praising the dictator Videla, whom human rights activists accuse of killing as many as 30,000 people in the 1970s "dirty war."
"They weren't 30,000, nor were they innocent. Happy birthday General! A soldier never asks for forgiveness for having saved his fatherland from a communist dictatorship," wrote the priest.
Poli said Hidalgo's gesture caused "confusion, sadness and a serious injury to the Church, and his expressions are far from who we are and our mission of love."