The Ontario College of Teachers, which oversees teachers in the province, has revoked Jacques Perron's licence and barred him from reapplying for it for at least five years.
The disciplinary committee panel did not explain its choice of sanction, saying it would issue a written decision later.
But in an earlier decision, it found Perron's inaction made him an accomplice to the abuse alleged to have taken place on multiple occasions between 2003 and 2006, including on school trips.
A lawyer for the college argued Wednesday revocation was the only acceptable penalty for a man who ran a French-language Catholic school near Thunder Bay like "his own personal fief" and failed to protect the children in his care.
"Mr. Perron was the school's principal and thus in a position of trust and of authority," Christine Lonsdale told the three-member panel.
"We can't rehabilitate him... A lesser sanction (than revocation) would undermine the public's confidence," she said.
Perron, meanwhile, called the ruling a gross miscarriage of justice based on false accusations from former students and colleagues with an axe to grind.
"I feel like a victim," he said after the hearing.
The allegations involve a man who worked as a custodian, educational assistant and lunch supervisor and a student described as "intellectually challenged."
Though many believed the custodian to be Perron's half-brother or his lover, Perron said Wednesday the man was in fact his ex-boyfriend but the two of them remained good friends after their romantic relationship ended.
He said he allowed the community to believe they were relatives because he felt homosexuality was frowned upon in the Catholic school system.
Perron's previous lawyer had told the panel his client was led astray by his affection for the other man, to the point of "deliberate ignorance" when faced with reports of abuse.
But at Wednesday's hearing, Perron's new lawyer said his client never agreed to make that statement and plans to appeal both the decision and penalty.
"Mr. Perron isn't perfect, but he never, never, never, never abused children" or admitted to ignoring such abuse, Jacques Roy said.
Details of the alleged abuse were outlined in previous hearings when the student at the heart of the case took the stand.
The student, whose identity is protected by a publication ban, testified the custodian "coerced him into sex several times a week" and shared a hotel room with him during two separate school trips to Winnipeg, according to the college's records.
Perron took part in one of those trips, though the student said he did not have sexual contact with him.
Under cross-examination, the student admitted he signed a letter at Perron's request denying the alleged abuse occurred, and said he wanted to protect his then-principal and mentor.
Other school employees testified they had complained to Perron about the custodian's behaviour toward that student and others, but were told the matter had been dealt with.
They also accused him of creating a culture of intimidation in the school in which favourite employees were given free rein while those he disliked were bullied.
The abuse allegations began to emerge while the school board looked into several unrelated complaints against Perron.
Provincial police were called in to investigate but said no charges were laid against him or the custodian.
In Ontario, the Child and Family Services Act requires anyone working closely with children to report any suspicion of abuse against a child.
Perron went on sick leave in 2004 to deal with stress stemming from a grievance filed by a former school employee.
He was later suspended without pay or benefits, then fired in November 2006.
He filed a lawsuit against the school board and brought a complaint to the Human Rights Tribunal of Ontario, claiming he was dismissed in part because of his sexual orientation.
But the suit was unsuccessful and the human rights case was settled out of court. Neither he nor his lawyer in that case would discuss the terms of the settlement.