ROME — Rushing to meet his wife at St. Peter’s Square, Thomas Williams walked past priests in black cassocks and said that the only thing he missed from his own decades of wearing a priest’s collar was “a real sense of helping people very directly.”
He paused and added, “I’m sure I’m helping people in some way.”
Mr. Williams’s current mission, since 2014, is in the service of Breitbart News, the populist, right-wing website that backed Donald J. Trump in his run for the presidency and is popular with the alt-right, an extremist and often xenophobic movement that embraces white nationalism.
The website is now hoping to buoy Europe’s surging anti-immigrant parties by spreading into Germany and France. But for years, Breitbart has had a presence in London, Jerusalem and Rome, which is perhaps most important for its imagining of itself as an expanding empire with a foothold in the ancestral home of the Crusades.
To man the fort in Rome, Stephen K. Bannon, then Breitbart’s chief executive and now Mr. Trump’s chief White House strategist, turned to Mr. Williams, a telegenic and polyglot theologian who had spoken for the Vatican and defended the leader of his conservative religious order against accusations of child molestation (ultimately proved true). Mr. Williams himself then left the priesthood in disgrace when it emerged that he had broken his vows of celibacy and fathered a son.
“You know my history,” Mr. Williams, 54, said, referring to a past worthy of its own Breitbart headline. “I was looking to re-establish myself again.”
He has done so by documenting the illegal immigration inundating Italy’s shores; tracking the country’s ascending anti-establishment movement; monitoring the religious persecution of Christians; and focusing on the Catholic hierarchy’s conservative reaction to Pope Francis.
Yet Mr. Williams, amiable and soft-spoken, seems a discordantly gentle voice in the strident Breitbart chorus.
He said his time in the public eye had made him extra sensitive to inflicting harm and he lamented the “horrible” Breitbart commenters. Referring to the laptop computer on his dining room table, he noted, with a hint of sarcasm, that his home office — where he keeps a reliquary of bone chips of Dominican saints and framed photographs of Pope Benedict XVI smiling with his mother-in-law, a former United States ambassador to the Holy See — was “pretty nondescript for a subversive, alt-right, world-changing organization.”
From the beginning of his talks with Mr. Bannon, he said, Mr. Williams had expressed wariness about the website’s tone.
“Breitbart seemed like the exact opposite of everything I had been trained for and naturally tended towards,” the former priest said. “Which was help people understand each other, smooth over differences, show maybe you are not as far apart as you think.”
Mr. Williams had first met Mr. Bannon in 2003 through a mutual friend who was producing Mel Gibson’s “The Passion of the Christ,” on which Mr. Williams worked as the theological consultant. (“Mostly just to say things like, ‘You can’t do that,’” Mr. Williams said.)
“I thought he was a little crazy,” Mr. Williams said of Mr. Bannon. “I knew he was in this media stuff and he had all these theories about everything.”
At the time, Mr. Williams was the face of the conservative Legion of Christ religious order. In 1997, Mr. Williams helped found the conservative Legion-sponsored Zenit news agency, and he has written 15 books, including “Knowing Right From Wrong: A Christian Guide to Conscience.”
Traveling in rarefied American church circles, he met Mary Ann Glendon, a prominent lawyer who, since 2013, has sat on a pontifical commission appointed by Pope Francis to investigate the Vatican Bank. She introduced Mr. Williams to her daughter, the Vatican art historian Elizabeth Lev. In 2003, Ms. Lev gave birth to Mr. Williams’s son, but kept her child’s paternity secret.
In the meantime, Mr. Williams became the go-to priest for Vatican analysis on American television and defended the leader of his order, the Rev. Marcial Maciel Degollado, from accusations of child molestation.
Pope Benedict forced Father Maciel to leave public ministry in 2006, and after the priest died in 2008, it was shown he fathered several children, and abused drugs and children. (“I thought he was innocent,” Mr. Williams said quietly, adding: “I was wrong.”)
In 2012, Mr. Williams acknowledged a news report that revealed his secret life and that he had fathered a child. He refused to identify the mother, apologized and went home to Michigan, where he said he “just kind of hid.”
A year later, Mr. Williams left the priesthood and returned to Rome to marry Ms. Lev and raise their son, who has Down syndrome. The three now live with Ms. Lev’s two adult daughters from a previous relationship.
Mr. Williams speaks adoringly of his son and accompanies him to therapy. He said he was “thrilled” to have his mother-in-law visiting for the holidays. He paints Roman street scenes for his wife and expresses appreciation for a “full life.”
But the circumstances of his leaving the priesthood had left him without an outlet for his considerable Vatican experience and academic expertise. That is when Mr. Bannon, seeking a presence for his website in a foundational spot of Judeo-Christian culture, came calling.
“Culture moves politics,” Mr. Williams said Mr. Bannon told him when pitching him to take the job three years ago. “Politics doesn’t move culture.”
Mr. Bannon, less than interested in food and fashion, often came to Rome to discuss the project.
“Eating with him is no fun,” said Mr. Williams, who wears a lapel pin that identifies him as a certified sommelier. At restaurants, Mr. Bannon paid no attention to what he ate and wore “a sport jacket with the cargo pants. It just looks silly, especially for Italians who care.”
But Mr. Williams said he was deeply impressed by Mr. Bannon and had never seen any evidence of his harboring racist or anti-Semitic views.
“The only place you could find anti anything is definitely toward Islam, there is some animus there,” Mr. Williams said, adding that he shared Mr. Bannon’s reservations about assimilating Muslims. He participated in a 2014 Vatican event where Mr. Bannon argued that the “church militant”needed to unite against secularization and an Islamic fascism “that will completely eradicate everything that we’ve been bequeathed over the last 2,000, 2,500 years.”
On other issues, however, there was considerable distance between Breitbart and its correspondent in Rome.
Mr. Williams was far less skeptical about European unity and the euro than the Breitbart line, which he called “obviously pushing this populism and very much anti-European.”
As Mr. Bannon began championing Mr. Trump as a way to blow up the establishment, Mr. Williams said he challenged his boss, telling him, “If you are going to tear down, you better know what you are building.” He added, “But I think he prefers tearing down to building up, honestly.”
When it came to immigration, Mr. Williams said he considered the symbol of a wall between the United States and Mexico “terrible” and fell in the middle between Mr. Trump’s hard-line position and the advocating of building bridges by Pope Francis, of whom he spoke respectfully.
Mr. Williams said that while his editors didn’t meddle in his coverage of the pope, they pressed for stories highly sympathetic to opponents of Pope Francis in the Vatican, especially the vocal Cardinal Raymond Burke, a friend of Mr. Bannon whom Pope Francis stripped of power.
Generally, Mr. Williams said, Breitbart considered Pope Francis a challenge. “Challenging in the sense that they don’t love the guy,” he said, adding that Mr. Bannon, who declined to comment, was “suspicious” of Francis.
Mr. Williams now dresses in a sports coat and jeans instead of clerical attire, but he still seemed entirely comfortable in the Vatican as he arrived at St. Peter’s Square to meet his wife. While he posed for a photograph, she considered how she liked being married to Breitbart’s man in Rome.
“I’m the wife of Thomas Williams,” Ms. Lev said with a smile. “And I love that.”