76-year-old John McClean worked at the private Dublin school Terenure College between 1973 and 1996 as an English teacher and rugby coach. He left the school in 1996 after allegations of abuse were made and worked as a rugby coach in UCD.
He will be sentenced next week on Thursday.
Between 1973 and 1990 he sexually assaulted 23 students on school grounds who were between the ages of 12 and 16. Nine were abused in an office, eight during costume fittings for school plays, three during sporting activities and three in the classroom.
McClean pleaded guilty to 27 charges of indecent assault in November 2020 after initially denying all charges. Further charges may still be filed.
Over the course of two days, victims took to the stand to read impact statements before Judge Pauline Codd. Fifteen spoke on Wednesday with the remaining eight speaking on Thursday.
One former student said that the abuse "was not [an] opportunistic event but the cold calculated actions of an odious man." He told of the self-destructive path that his life took after being repeatedly abused by McClean, which ultimately resulted in his mother sometimes calling him "the devil."
He told the court that he had come to realize that his mother was wrong and he was not the devil. He had "just crossed paths with the devil at Terenure College."
"I'll never forgive or forget what he did," one victim stated. "He ruined my life when he was supposed to be protecting me." The man, now in his 50s, had found out years after the abuse that his older brother had also been abused by McClean.
Another former student arranged his own expulsion from the school in order to escape the abuse.
The court heard that as far back as 1979 a student had come forward to administrators about allegations of abuse during a costume fitting for a school play. While McClean was removed from that duty, he was given a private office in 1981 after being appointed as first year headmaster where the abuse continued.
During the second day of testimony, the court heard that McClean had confessed the abuse to a senior priest 25 years ago after one of the fathers of a victim brought forth allegations in 1996. Father Robert Kelly informed the father that the matter needed to be reported to the gardaí.
Inspector Jason Miley confirmed that a report had been filed by Kelly and that the file notes indicated that Kelly had spoken to McClean about the allegations and he had admitted to them. Kelly testified that while he had no specific memory of the meeting, if the admission was recorded in the notes, then it must have been true.
Speaking on behalf of McClean, Mr. Guerin stated that his client wished to express his unconditional apology to the victims and their families saying that he is "very, very sorry for what he did."
During one of the victim statements on the second day, one man expressed his disgust with the "grotesque and manipulative" truth of who McClean was behind a "mask of respectability and cloak of authority," also calling him a "monster in disguise."