Andrew Soper, 74, is likely to die in prison after being found guilty of a string of sex attacks on boys in the 1970s and 80s.
He fled to Kosovo with £182,000 from the Vatican bank in a bid to avoid responsibility for the abuse at fee-paying St Benedict's School in Ealing, west London.
But the former Ealing abbot and headmaster, known as Father Laurence, was extradited to face 19 charges of indecent assault and buggery against 10 former pupils.
On being found guilty at the Old Bailey, the school apologised unreservedly for the "serious wrongs of the past".
Soper's victims were supported by relatives in court when he appeared to be sentenced.
The court heard Soper still maintained his innocence and described his conviction as a "miscarriage of justice".
The court heard he has already been attacked while on remand at Wormwood Scrubs and is now being held in segregation for his own protection.
Sentencing, Judge Anthony Bate said his conduct was "the most appalling breach of trust" and he had "subverted the rules of the Benedictine order and teachings of the Catholic Church".
He told Soper: "You have been a clandestine sex offender since your early 30s."
He said his life would now be "overshadowed by the proven catalogue of vile abuse".
He added: "Your disgrace is complete."
The school counts former Conservative chairman Lord Patten and entertainer Julian Clary among its old boys and currently charges fees of around £5,000 a term.
It had come under scrutiny in the past, with both violence and sexual abuse by the adults in charge said to be "prevalent".
Prosecutor Gillian Etherton QC had told how the victims were subjected to sadistic beatings by Soper for "fake reasons".
They included kicking a football "in the wrong direction", "failing to use double margins", and "using the (wrong) staircase", leading to a caning and a sexual assault, she said.
Ms Etherton said at least one of Soper's alleged victims subsequently suffered serious mental health problems, while another was too afraid to speak out because the abusers "were like saints to me".
The court heard Soper quit as an abbot in 2000 and moved to Rome then skipped bail and spent six years living in Kosovo, with a European Arrest Warrant issued for his extradition.
Giving evidence, Soper denied using the cane as a ruse to abuse boys who were given the choice of six lashes with trousers on, or three with them off.
He told jurors he went on the run out of "stupidity and cowardice", fearing that his life's work would be wrecked.
He said: "If you want to destroy a priest, vicar, anybody, all you have to do is make an accusation up against them. Their future is ruined, their character is ruined."
Soper was on first name terms with Cardinal Basil Hume and knew Lord Patten, who worked on the advisory panel while he was abbot, the court heard.
Statements by Soper's victims were read out in court, detailing the effect of his abuse on their lives.
One described how he had aspirations to be a vet or pilot before his life was ruined. He was "drinking to numb the pain of what was happening to him as a young boy".
Having been brought up a strict Catholic, he had since lost his faith. He said: "I have tried countless times to take my own life - I just could not cope."
Soper is the latest in a string of men to face allegations relating to their work at St Benedict's.
In 2009, Father David Pearce, 75, nicknamed the "devil in a dog collar", was jailed after he admitted 11 charges of indecent assault dating back to 1975.
Between 2003 and 2009, "master of discipline" John Maestri, 78, of Chatham in Kent, admitted five indecent assaults against children at St Benedict's in the 1970s and 80s and was jailed.
In 2010, John Skelton was convicted of indecent assaults against two complainants said to have occurred in 1983 at St Benedict's.
Father Anthony Gee faced accusations of abuse, but no further action was taken although civil action was brought against him, jurors were told.
In a statement, Lord Carlile QC said on behalf of the school: "The tough lessons of the past have been learned, and the errors and crimes of the past are in the daily consciousness and conscience of the school management.
"Child safeguarding is the top priority, alongside the highest level of teaching and the provision of an excellent learning experience."
Ealing Abbey said in a statement: "Andrew Soper has finally been brought to justice.
"Our thoughts and prayers are with his victims. We admire them for their courage in coming forward as witnesses in order to secure his conviction.
"We apologise to everyone who is affected by the crimes Soper committed while he was a monk of Ealing and a teacher at St Benedict's School in the 1970s and 1980s.
"The prosecution of non recent sexual offences is important element in ensuring that, so far as possible, such events do not occur in future."
Detective Superintendent Ang Scott, of Scotland Yard, said: "Soper abused his position of trust as headmaster of a middle school over a sustained period of time.
"I would like to pay tribute to the victims in this case for the bravery they have showed in coming forward and reporting these offences and giving evidence at court.
"Although it can never make up for the emotional and psychological trauma caused by Soper's crimes, I hope the sentence handed to him today can give them some form of closure."
The NSPCC said Soper "subjected his victims to sustained, sickening abuse".
A spokesman said: "The impact of that suffering will have had consequences not only during childhood but also into their adult lives.
"This case highlights once again that victims of past abuse can come forward and achieve justice no matter how long ago the offences took place and no matter who their abuser is."
