Archbishop Jose Gomez said he had stripped his predecessor, retired cardinal Roger Mahony, of all public and administrative duties.
Mahony’s former top aide, Thomas Curry, stepped down as bishop of Santa Barbara.
“I find these files to be brutal and painful reading. The behaviour described in these files is terribly sad and evil,” said Gomez in a statement released by the nation’s largest Catholic archdiocese.
“There is no excuse, no explaining away what happened to these children. The priests involved had the duty to be their spiritual fathers and they failed.”
A spokesman for a victims’ support group said the removal of Mahony and Curry was long overdue.
“Hand-slapping Mahony is a nearly meaningless gesture,” David Clohessy, director of the Survivors Network of those Abused by Priests said. “When he had real power, and abused it horribly, he should have been demoted or disciplined by the church hierarchy, in Rome and in the US. But not a single Catholic cleric anywhere had the courage to even denounce him. Shame on them,” he said.
The 12,000 pages of files were made public more than a week after church records relating to 14 priests were unsealed as part of a separate civil suit, showing church officials plotted to conceal the molestation from law enforcement as late as 1987.
Those documents showed that Mahony, 76, and Curry, 70, his top adviser, both worked to send priests accused of abuse out of state to shield known molesters in the clergy from law enforcement scrutiny in the 1980s.
They also tried to keep priests, sent away to a Church-run paedophile treatment centre, from later revealing their misconduct to private therapists who would be obligated to report the crimes to police.
Among the documents released was the personnel file of Fr Jose Ugarte, which contains a 1993 letter to an archdiocese official from a man whose name was redacted and whowrote that Ugarte began sexually abusing him in 1983 when he was 17.
A document in the file says that in 1994, then Archbishop Mahony and Ugarte reached an agreement requiring the Spanish priest to “leave the US and take up permanent residence in Spain” and not to return without the express consent of the archbishop of Los Angeles for seven years. The final outcome in that case was not immediately clear.
Patrick Wall, 47, a former priest who is a consultant for plaintiffs and prosecutors in Catholic sex abuse cases, said the files suggested that Mahony had been trying to avoid a public legal case against the priest.
Los Angeles prosecutors have said they will review and evaluate the documents, the archdiocese has said.
The Los Angeles arch-diocese, which serves 4m Catholics, reached a $660m (€480m) civil settlement in 2007 with more than 500 victims of child molestation.
It was the biggest such agreement of its kind in the nation, and Mahony at the time called the abuse “a terrible sin and crime”.
Victims’ advocates have accused Church leaders of continuing to obfuscate their role in the scandal, and cite the newly released files as a “smoking gun” proving complicity by Mahony and others.