St Ronan's Lurgan clinched the Hogan Cup All-Ireland Senior Schools Football title by edging out Rice College Westport 1-10 to 1-9 at Croke Park.
The Mayo school led 1-5 to 0-6 at half-time but Tiernan Kelly's goal put the Armagh team ahead.
Rice College had chances to force extra-time but again it was a case of Mayo disappointment at Croke Park.
Earlier, Holy Trinity Cookstown earned a 0-19 to 1-6 win over St Nathy's Ballaghadereen in the B final.
The Tyrone team led 0-9 to 0-2 at half-time and were never in any danger of being caught as Kuba Callaghan hit a late goal for St Nathy's.
St Ronan's add All-Ireland honours to their first MacRory Cup title which they earned by beating St Mary's Magherafelt on 19 March.
The Lurgan school then defeated Kerry side Pobalscoil Chorca Dhuibhne 2-10 to 1-10 in last week's All-Ireland semi-final.
St Ronan's, only founded three years ago, were forced to defend hard late on, as their opponents went in search of the winning score on three occasions, but failed to reap dividends.
A 52nd-minute score from Oisin Smyth proved to be the match-winner in a very tight and competitive affair.
A fisted effort from Keith Joyce provided the only goal of an opening half, where St Ronan's had two goal chances, but Cian Kennedy denied Rioghan Meehan and Ruairi McConville on separate occasions.
On the re-start the sides traded early points, before Jack Lenehan had a goal miss - a rasping shot coming off the upright.
Slowly but surely St Ronan's got on top, and found a vital goal in the 38th minute, when a Smyth effort was blocked, before Kelly edged the ball to the net.