Trevor Bolton, 78, from Clacton-on-Sea, Essex, targeted eight boys over 20 years at Carmel College in Oxfordshire.
The former housemaster has been convicted of 16 counts of indecent assault, six counts of indecency with a child, and three other sexual offences.
Victims Peter Gluckstein and Stephen Raynor-Endelman told BBC News they were relieved by the verdicts.
Bolton carried out his crimes against boys aged 11 to 15 between 1968 and 1988.
During the trial, one of the victims said at the time Carmel College was regarded as the world's premier Jewish school.
It was based Mongewell Park in Wallingford, but closed in 1997.
The court heard the housemaster and French teacher lived on site and told the boys they could visit his home when they felt homesick.
Two of his victims have waived their anonymity to speak publicly.
Mr Gluckstein, 56, from London, was abused by Bolton from the age of 11.
He said the teacher would help him with his homework and invite him to his flat, where the sexual abuse would take place.
"I would be screaming inside my head for it to stop, but I would still go back," he said.
"I still don't really understand the process, the neediness that meant you go back even though you hated it."
Carmel College was founded by Rabbi Dr Kopul Rosen in 1948 and closed in 1997
It was originally based at Greenham Common, Berkshire, but moved to Mongewell Park in 1952
During its life the school was attended by about 4,000 students - a third from overseas
A 1973 edition of the Observer described it as "the Jewish Eton"
Source: Carmel College website
Stephen Raynor-Endelman, 53, who is now a composer and lives in Los Angeles, was also groomed by Bolton from the age of 11.
He said: "I was invited up to sit next to him in the classroom, then we'd have lunch together, and it was kind of an enviable position for the other boys.
"He was man of major importance and a very significant figure of power and authority."
Bolton will be sentenced at Oxford Crown Court on Friday.
Two men have described being subjected to years of sexual abuse by a teacher at a leading former boarding school.