Pope Francis has accepted the resignation of Archbishop Donald Wuerl of Washington, D.C., the Vatican announced Friday, two months after a sweeping report claimed the powerful U.S. archbishop allowed priests accused of child sex abuse to be reinstated or reassigned.

"The Holy Father's decision to provide new leadership to the archdiocese can allow all of the faithful, clergy, religious and lay, to focus on healing and the future," Wuerl said in a statement.

"Once again for any past errors in judgment I apologize and ask for pardon. My resignation is one way to express my great and abiding love for you, the people of the Church of Washington."

Wuerl, 77, a key ally of Francis and the most prominent head to roll in the scandal shaking the Roman Catholic Church, stepped down after the grand jury report in Pennsylvania found that more than 300 priests in the state sexually abused minors over a 70-year period. Wuerl was the bishop of Pittsburgh from 1988 until he took over the Washington archdiocese in 2006.

On Sept. 11, Wuerl announced he would ask Francis to accept his resignation. Since then, parishioners, Roman Catholic schoolteachers and even a handful of Wuerl’s own priests called for him to resign.

Wuerl has denied knowing that his predecessor, former Archbishop Theodore McCarrick, was suspected of abusing young men studying for the priesthood. This prompted criticism from some clergy members and advocates for victims who said that they found it hard to believe that as archbishop he did not know about the allegations.

Pressure on him and the Vatican surged on Aug. 26, when Archbishop Carlo Maria Vigano, a former papal ambassador to the U.S. and a longstanding critic of Pope Francis, released a letter stating that senior clerics, including the pope and Wuerl, knew about McCarrick’s behavior but did little or nothing to stop it.

In one example in the letter, Vigano said he had asked Wuerl to cancel a recruitment event with McCarrick and potential seminarians, which Wuerl immediately agreed to. This raised questions, Vigano said, about why Wuerl would agree if he knew nothing of the allegations.

On Sept. 13, as a U.S. delegation met with the pope over the latest chapter in the scandal that has also embroiled Francis himself, the Vatican authorized an investigation into another U.S. bishop accused of sexual harassment of adults. The Vatican announced that Pope Francis had accepted the resignation of West Virginia Bishop Michael Bransfield, a close associate of McCarrick’s.

Wuerl was initially considered to be at the forefront of dealing with the clerical sexual abuse scandal when, as bishop of Pittsburgh, he refused a Vatican order to return a credibly accused priest to ministry. But the grand jury report also showed he still returned other predator priests to ministry upon the recommendation of psychologists.

“He has shown that he has been involved in a number of cover-ups,” Terrence McKeegan, a former legal adviser to the Vatican’s observer mission to the United Nations in New York, told NBC News. “The bishops largely know about a lot of these issues, and so when they claim publicly that they have no knowledge they really lose a lot of credibility.”

The resignation marks the end to a storied career for a priest who many saw defined by fierce loyalty to three pontiffs, including Francis, rather than the culture wars that shaped the careers of many other American bishops.

Pope Francis, left, talks with Papal Foundation Chairman Cardinal Donald Wuerl, Archbishop of Washington, at the Vatican. L'Osservatore Romano / AP file

Several priests who know Wuerl and spoke to NBC News on conditions of anonymity for fear of jeopardizing their relationship with him say the pope’s letter accepting his resignation should have been more strongly worded in encouraging Wuerl to acknowledge his mistakes.

Becky Ianni, director of the Washington, D.C. chapter of SNAP—Survivor Network of those Abused by Priests—says the pope's letter accepting Wuerl's resignation, and asking him to remain as apostolic administrator until a successor is appointed was a “slap in the face to victims."

"I'm not going to count on the church to do what's right," she said. "I mean this is sort of like the last straw."

Though Wuerl may no longer be the leader of Washington’s more than 650,000 Catholics, he’s still expected to wield considerable influence in the American church, as a member of the Congregation for the Doctrine of the Faith — the Vatican’s theology watchdog — and in the selection of new bishops.

The crisis in the U.S. church has also become a rare unifier of both conservative and liberal Catholics calling for continued investigations of church leadership, and prompted attorney generals from more than a dozen states to launch investigations of their own.

“For too long, bishops have been in charge of policing themselves,” the Rev. Jim Martin, editor-at-large of the Jesuit magazine America and a consultant to the Vatican’s Secretariat for Communications, told NBC News. “So the question is summed up by the Latin phrase, Quis custodiet ipsos custos? Who guards the guardians?”

Matthew Vann reported from Washington; Anne Thompson from New York; and Claudio Lavanga from Rome.