Parks scaled the 29,036 foot high peak on the same day as his mountaineering companion, the former double Olympic gold medallist rower Steve Williams, who joined him for the latest challenge of his worldwide expedition.
Parks now has just two more summits to climb to make history as the first ever person to stand on all seven of the world’s highest peaks and reach the North and South poles in the same calendar year.
He will now head for Alaska to climb Denali, the highest mountain in North America before finishing his record breaking challenge climbing Mount Elbrus in Russia, the highest mountain in Europe.
The Chairman of the WRU, David Pickering, said: “I want to congratulate Richard for an historic achievement which keeps him on track to achieve a goal many believed was beyond the capabilities of endurance.
“To summit Everest is a remarkable achievement in itself but given what Richard has already put himself through in recent months it is truly amazing.
“He should be proud of himself as a credit to his friends and family, his nation and to the sport of rugby in which he first proved his physical prowess as a first rate player.
“We have been watching his progress with increasing admiration and now wish him well for the next stage of the 737 Challenge.”
The Group Chief Executive of the WRU, Roger Lewis, echoed the chairman’s praise and added: “Richard has already achieved goals on the 737 Challenge expedition which prove he is an incredibly determined athlete.
“When the crowd gave Richard a send off from the Millennium Stadium in last year’s Invesco Perpetual Autumn International Series it was a moment of inspiration I know he cherished.
“Now I wish him a safe journey onwards in the knowledge he is capable of achieving astonishing goals through his determination and skill.”
Parks was forced to retire from professional rugby with a shoulder injury almost two years ago.