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”.
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”.
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.
Soper is the latest in a string of men to face allegations relating to their work at St Benedict’s.
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.”
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.