His efforts, backed by a host of support agencies, have seen teenage pregnancies in the city plummet and raised awareness of sexually-transmitted diseases (STDs).
Giving away free condoms to school children as young as 13 is one reason for the city's success.
But Mr Campion says there is still more to do to help bridge the "generation gap" blighting progress. He believes teachers should talk about sex in the same uninhibited way that they would go about explaining an essay or equation, with some added "emotional empathy".
But his proposed revolution in sex education has met opposition from some secondary heads opposed to spending more time on PSE rather than academic studies, and teachers who believe "sex is best left in the bedroom".
To build on this, Mr Campion believes teachers have to get into touch with today's teenager - and fast. That was what Sex in the City, a conference bringing together young and old, was about, and it was definitely not for the easily offended or prudish.
Educationists, GPs, charity workers, genito-urinary medicine clinic representatives, helpline workers, schoolchildren and the children's commissioner for Wales, Peter Clarke, all joined together in a frank and open discussion of all things sexual last week in Swansea.
The conference was part of a city-wide strategy to combat teenage pregnancy and STDs through good sex education, inter-agency co-operation and, as Mr Campion puts it, "let's talk about sex" teachers. He claims this can only have a positive impact on exam results.
"The teenage mum who falls out of the exam system might have gone on to get seven A-C grade GCSEs if her unplanned pregnancy had been prevented, it stands to reason."
But he is adamant good sex education cannot be given by teachers who do not want to do it. He is trying to gather support to give special training to teachers who want to teach PSE, and make it their exclusive domain.
He is also fighting for every school to have a private room set aside for young people with a sexual problem or query. And he hopes his work will be backed up with funding for a school-based multi-agency support centre, modelled on a pilot scheme in Newcastle, which has helped reduce teenage pregnancy and STD rates, increased pupil self-esteem and raised achievement.