Mexico is the second-biggest Catholic country after Brazil with around 80% of its nearly 130 million people affiliated with the church. It has historically been conservative-leaning on social issues.
Cardinal Carlos Aguiar, archbishop of Mexico City, said in an interview that he backs the pope's comments from a documentary that premiered in October and used previously unseen footage from an interview he gave to Mexican broadcaster Televisa. The comments marked the first time a sitting pope had advocated any legal protections for gay couples.
"I completely agree," said Aguiar, a long-time ally of Pope Francis, who spoke ahead of Saturday's feast day of the Virgin of Guadalupe, one of the Mexican Church's most important annual celebrations.
In the documentary, entitled "Francesco," the pope says, "Homosexual people have the right to be in a family, they are children of god," and "what we have to have is a civil union law, that way they are legally covered."
The pope's comments did not signal any change in church doctrine on homosexuality or support for same-sex marriage, which the Vatican emphasized after the remarks made headlines across the globe.
But Francis' more open and inclusive tone has marked a sharp contrast with his more conservative predecessor, Pope Benedict XVI.
"All of us are children of god, all are members of the family, and if we're fighting so that families are united, regardless of their conduct, they don't stop being our children. And that's what Pope Francis said, everyone has the right to family," said Aguiar.
The cardinal, who has lobbied against both abortion rights and same-sex marriage, argued that parents should never reject their openly gay children.
"Because if, as it happens unfortunately, a son in a family declares himself openly homosexual, then they don't want to have anything to do with him. And that can't be, it just can't be," he said, echoing Francis' sentiments.
"If they decide as a matter of free choice to be with another person, to be in a union, that's freedom," he said.
Like the Argentine pontiff, the 70-year-old Aguiar touts landmark church reforms in the 1960s that pushed the church closer to the faithful and also embraced a social teaching aimed at alleviating human misery, while focusing less on what Aguiar called the "clerical mentality" that prioritizes the institution.
"The key point was to move away from a church that defended itself from the world," he said.
Aguiar added that much work remains to address poverty and inequality in Mexico and the surrounding region.
"Latin America is the part of the world that's most unequal," he said, "and many of us here are Catholic!
"What kind of witness is that?"