Even more remarkable has been his talent for turning on more of the less academic pupils who might otherwise be lost to the system for ever.
Attendance rates have shot up as the most disengaged tune in to new vocational subjects offered at the school. This is also reflected in the results, with 94 per cent of pupils gaining A*-G passes at GCSE last year - 12 percentage points higher than four years ago.
Speaking at a recent conference of the Association of School and College Leaders Cymru, Mr Stacey told how he axed subjects on the basis of hard statistics. His brutal methods go hand in hand with a strong belief that if subjects are not producing results, they are not good for the school or pupils. There were a few raised eyebrows among the audience of fellow heads when he cut to the chase.
Some may argue that offering girls health and fitness when they could be the next Dame Kelly Holmes is clearly off the pulse. The same could be said for not offering business studies on the curriculum. How will we nurture the next Welsh tycoon? Another Terry Matthews or Stan Thomas?
Of course, there are many outstanding heads and teachers in Wales doing brilliant jobs in raising pupil achievement against the odds.
But what is admirable about Mr Stacey is that he makes decisions, sticks by them and is clearly coming out on top.
But the bottom line is that he won't condemn his pupils to failure. Until his results show otherwise, this head must surely be given one big pat on the back.