Facing trial on Monday over abuse allegations dating as far back as the 1940s, the archdiocese led by Cardinal Roger Mahony agreed to pay 508 victims the largest-ever group settlement on Sunday.
"I have come to understand far more deeply that I ever could the impact of this terrible sin and crime that has affected their lives," Mahony said.
"There really is no way to go back and give them that innocence that was taken from them," he said. "I apologise to anyone who has been abused. It should never have happened and it should never happen again."
Jeff Anderson, a lawyer representing alleged victims of abuse, told Al Jazeera that as part of the settlement, the archdiocese agreed to disclose files allegedly documenting the abuses, indicating that the leadership knew of the crimes.
He said the archdiocese had settled to avoid the scrutiny it would have received during trial.
Victims allege Mahony did not deal properly
with complaints against priests [Reuters]
Victims allege Mahony did not deal properly with complaints against priests of abuse, and the settlement spares him difficult questions in court.
Barbara Blaine, founder of the Survivors Network of those Abused by Priests, said "Cardinal Mahony and other church leaders would have had to take the witness stand under oath and tell the truth about how much they knew and how little they did with that knowledge to protect the children".
"What we would have seen is the horrors with the reality that hundreds of children were sexually assaulted, raped, sodomised by priests when the leadership of the church knew."
The settlement was the latest chapter in a clergy abuse scandal that has rocked the Roman Catholic Church worldwide, damaging its reputation and causing five US dioceses to seek bankruptcy protection.
Some victims say the money will not ease their physical and emotional suffering.
Mary Grant, who said she was sexually abused, told Al Jazeera: "I as well as hundreds of other survivors who filed these lawsuits, filed them because church officials like Cardinal Mahony and others refused to inform parishioners of the priests who abused them or removed them from parish ministries."
Steve Sanchez, 47, one of 12 victims who had been scheduled to go to trial, said: "I have a mixed reaction. "There's a group of victims who have been fighting this publicly and ready to take on the church publicly, probably a handful. At the same time there is a large group of victims who did not want to go through with the process, being in the public."
Sanchez, a financial planner, said he and his brother were abused by Los Angeles priest Clinton Hagenbach, who died in 1987.
Tod Tamberg, a spokesman for the Los Angeles archdiocese, said Mahony would be in court on Monday as lawyers seek the judges' approval of the settlement.
Individual victims will receive between $100,000 and $4m each, said Ray Boucher, a lawyer for the plaintiffs.
A lawyer for the church said a third to half of settlements typically goes to plaintiffs' attorneys as compensation in contingency cases.
The lawyers declined to discuss their fees.
J Michael Hennigan, a lawyer for the archdiocese, expects payments by the end of the year.
He said the church would sell real estate assets, including the Los Angeles Archdiocese headquarters and perhaps some high schools, to raise the funds.
Hennigan said the church would fund about $250m of the $660m settlement, with the rest coming from insurers including Chubb, AIG, Allianz and Fireman's Fund with whom the church holds general liability policies, as well as several Catholic orders.
The Catholic Church, in which priests take a vow of celibacy, has faced abuse allegations worldwide over the past decade.
Some US dioceses have reached financial settlements with victims.
The Boston archdiocese, where the US scandal erupted in 2002, reached a 2003 deal for 550 people worth $85m.
But victims have had special leverage in California because state legislators have authorised an exception to the statute of limitations for old abuse complaints.