The departures of Burke and his deputy, Paloma Garcia Ovejero, signaled that the problems associated with Francis' reform of the Vatican bureaucracy had come to a head, and at a very bad time: The pope is struggling to address a global sex abuse and cover-up scandal that threatens his own legacy.
Francis nevertheless accepted the resignations, which take effect Tuesday, the Vatican said in a statement. He named a longtime member of the Vatican's communications operations, Alessandro Gisotti, as an interim replacement for Burke.
"At this time of transition in Vatican communications, we think it's best the Holy Father is completely free to assemble a new team," Burke tweeted. "New Year, New Adventures."
Burke stressed that he and Garcia prayed about the decision "for months and we're very much at peace with it." Both thanked the pope.
"One stage is ending. Thank you for these two and a half years," Garcia tweeted.
The pope recently overhauled the Vatican's media operations for the second time by ousting the longtime editor of the Vatican newspaper, L'Osservatore Romano, and naming a new director of editorial content for all Vatican media, Italian journalist Andrea Tornielli.
The resignations appeared to take the new team by surprise, though the job of Vatican spokesman is notoriously difficult given the feudal nature of the Vatican, its reflexive tendency toward secrecy and the occasional skepticism of journalists.
The head of Vatican communications, Paolo Ruffini, said he respected Burke and Garcia's decision. He praised their professionalism and said he had full confidence in Gisotti, who was a longtime journalist with Vatican Radio and more recently worked as the Vatican's head of social media.
"The year ahead is full of important appointments that will require maximum communications efforts," Ruffini said in a statement.
The comment might have referred to a high-stakes summit on preventing clergy sex abuse that Francis convened for February, as well as the pope's foreign trips planned for 2019: Panama, United Arab Emirates, Morocco, Bulgaria and Macedonia in the first half of the year, and rumored trips to Madagascar and Japan in the second half.
Francis still faces continued fallout from the clergy abuse scandal, in Chile, the United States and beyond. The next year will likely see the outcome of a canonical investigation of ex-Cardinal Theodore McCarrick, who has been accused of sexually abusing minors and adult seminarians in the United States, as well as the results of the Vatican's investigation of McCarrick's rise through church ranks.
Longtime Vatican watcher Rocco Palmo tweeted that the standard rule in crisis communications is "you don't leave in the middle of the storm but ride it out.
"To lose both the Vatican's top press hands (both quite devout) in mid-scandal appears to signal that something has become professionally untenable," Palmo tweeted.
Burke was a Fox TV correspondent in Rome when he was hired as a communications adviser for the Vatican's secretariat of state in 2012. At the time, the papacy of Pope Benedict XVI had suffered a series of communications blunders, and it was thought that Burke could provide guidance.
In 2015, Burke was named deputy spokesman under the Rev. Federico Lombardi, an Italian Jesuit.
When Lombardi retired in 2016, Burke became main spokesman and was joined by Garcia, the first woman to ever hold the position of deputy. Garcia had been the Vatican correspondent for the Cadena Cope, the Spanish broadcaster.
The two had internationalized the media operations, organizing unofficial briefings with visiting prelates, providing background information and streamlining communications with journalists during foreign trips.