Kevin O'Hare, 15, got into trouble at a disused quarry in Annalong, Co Down, on Saturday evening.
Colin Polland, 39, died when he tried to rescue the teenager.
Joan McCombe, principal at St Malachy's High School in Castlewellan where Kevin was a Year 11 pupil, remembered the keen GAA player as a "wonderful young man".
"Kevin was a wonderful ambassador for St Malachy's - a young man that embodied goodness and kindness, a son that any parent would be proud of, and a student that we as teachers were privileged to know," she said.
"When he put on the school jerse,y he played with commitment, he played with passion and the school teams will be the poorer because of Kevin going. He will be sadly missed by us all. Kevin was a well-respected, popular and highly-regarded student."
Mrs McCombe said she had met with Kevin's family, and the school's pastoral team are working with students at teachers at St Malachy's.
Today we are a school in mourning, but we are also remembering Kevin as the wonderful young man who came into this school.
"On behalf of the governors, staff and students of St Malachy's, I extend deepest sympathy and condolences to Kevin's parents, brothers and wider family circle. They are in our thoughts and prayers at this most sad and difficult time," the head teacher added.
The bodies of Kevin O'Hare and Colin Polland were found at Paul's Quarry in the Glassdrumman Road area near the seaside village on Saturday evening.
Mr Polland is understood to have jumped into the water at the isolated quarry in a bid to save the teen, who had got into difficulties when swimming in the quarry, but both died.
Environment Minister Alex Attwood says there are 3,000 disused quarries in NI.
The SDLP minister had previously written to councils asking them to review quarries in their areas and to improve safety measures.
"I first wrote to local councils in March, asking that each council reviews all disused quarries in their council area, conduct physical inspections, evaluate each site including risks and work, including with landowners and quarry owners, to resolve foreseeable risk," he said.
"The councils have legal responsibilities around disused quarries."
Tragically, over the past few years, a number of people have died or been seriously injured after entering disused or working quarries.
Environment Minister Alex Attwood
Mr Attwood added: "This work has commenced in a number of councils. It needs to accelerate, to identify what measures are needed to reduce risk and increase responsibility."
Police and emergency services were at the scene as the bodies were recovered.
Mr Polland was originally from Northern Ireland but had been living in England, and it is understood he was back in the region on holiday.
Sinn Féin councillor Paul Gribben said the deaths had sent shockwaves through the county.
"The family is in total shock ,as is the whole community," he told UTV. "Like any young lad at 15, Kevin was out to have a good time and on this tragic day lost his life.
"Our thoughts and prayers go out to both families."
Alliance South Down Councillor Patrick Clarke said: "I would like to commend the efforts of the PSNI divers, the Fire and Rescue Service, and the coastguard who were involved in trying to rescue both men."
DUP South Down MLA Jim Wells described the incident as an "awful tragedy", adding that the local community was "shocked to learn of the loss of life of a man and boy as a result of drowning."
A police investigation is underway to determine the circumstances surrounding the deaths.