A former British kick-boxing champion who was jailed for a string of violent offences in the 1990s has been allowed to register as a teacher.
A General Teaching Council for Wales panel heard Julian Konten, 36, has six spent convictions - mostly for serious assault - at a suitability hearing in Cardiff this week.
But the panel decided he should be allowed to register as a teacher after hearing that he had turned his life around and was proving to be an inspirational teacher.
Mr Konten has been working as a technology instructor at Willows High in Cardiff since last September, after training to be a teacher at the University of Wales, Newport.
Despite his having declared his convictions, the school offered him a teaching position. But in order to register him as a teacher, the GTCW had to consider whether his violent past - including an assault on a police officer - should bar him from the profession.
Mr Konten has been to prison twice. In 1994, he was sent down for two years after being convicted of an unlawful wounding charge and two separate offences of assault. In 1998, he was jailed for six months for dangerous driving.
Alison Love, the presenting officer for the GTCW, said: "These are serious matters. The assault in relation to a police constable demonstrated a failure to accept authority. By the time of the last offence, the applicant was 26. I would suggest he should have been aware of the consequences of his actions."
David Evans of the NUT Cymru teachers' union, representing Mr Konten, told the panel that several of the offences had taken place while he was in a "tempestuous relationship".
Mal Davies, head of Willows High and chair of the GTCW, submitted a written statement supporting Mr Konten.
Steve Davies, the school's deputy head, told the committee he would have employed Mr Konten despite his previous convictions.
"He is an inspirational teacher. He does an exceptionally good job. He is sought out by pupils often, and he does a lot more than he needs to do," he said.
Mr Konten described a colourful past in which he was offered a job dancing with Madonna and later became a British champion kick-boxer. He was the first person in his family to go to university.
Mr Konten, who has previously worked as a bouncer in Cardiff, told the panel he had successfully defused arguments in the classroom.
"A pupil said to me, 'Sir, you're a teacher, but you're from the docks'," he said. "I have tried to let the pupils know that education is the most important thing in their lives. I try and get them to see sense and know right from wrong."
He also said he was truly sorry for his crimes. "I was never a bad person, but I was out of control with my emotions and my feelings."
In his summing up, Mr Evans said: "Mr Konten is probably someone who could inspire a Hollywood film. All that remains for the perfect story is the feel-good factor at the end."
The suitability panel obliged. John Collins, its chair, said the panel was satisfied that Mr Konten was not a risk to children, colleagues and parents.
"The offences were serious and, at the time of the conviction, suggested a propensity toward violence. (But) he has demonstrated his commitment to the profession and enthusiasm for working with children under difficult circumstances."