The building is State property which had fallen into terrible disrepair. The public will have free access for a number of weeks over the summer to the restored manor in the tourist town.
Furthermore, the Irish Museum of Modern Art is “to expand its reach” and showcase its collections in the 18th-century structure and adjoining new exhibition centre, Minister Heather Humphreys announced.
She cut a ribbon to mark the end of a five-year restoration project funded by the Office of Public Works and Failte Ireland.
Restoration included extensive works to acres of gardens, to bring them back to their Edwardian glory along with the repairing of antique furniture including the original golden gates.
The high iron gates painted in gold which hid the magnificent grounds for hundreds of years and behind which sheltered the earls of Kenmare and, in the second part of the 20th century, the Irish-American McShain family.
The late John McShain, known as “The Man who Built Washington” for his major public buildings projects including the White House and Pentagon, bought the estate in the 1950s.
Afterwards, he donated over 8,000 acres of what is now the Killarney National Park to the State. He sold the remainder, including the house, to the OPW in 1979.
The State took complete control in 1999, on the death of his wife Mary.
However, controversy followed for the best part of the last decade after the house fell into disrepair.
Sr Pauline McShain, the only child of the McShains, sent her apologies yesterday as the House was officially opened to the public.
A great grand nephew of John McShain, Dylan McShain, had visited the property recently.
A lengthy email from him was read out by Pat Dawson, now manager of the house.
“How much did we own?” Dylan had asked caretaker Harry O’Donoghue, who had worked for the McShains, as the pair surveyed the great house and parkland.
“As far as the eye can see,” Harry had told him. The visitor told Harry he was not bitter at the family losing it.
In fact, Dylan said, it had filled him with great joy to see a young couple, an old man other members of the public enjoying what once had been a mystery “hidden behind the golden gates”.
Caretaker Mr O’Donoghue, now employed by the OPW, is the third generation of his family to work behind the high walls of Killarney House. His family had also worked for both the previous owners, the Kenmares, the former noble owners, and the McShain’s.
“I am delighted it’s open for the people of Killarney,” Mr O’Donoghue said yesterday.
Last week, in advance of the reopening, manager Mr Dawson said Mr O’Donoghue had advised on the proper china and crystal setting of the magnificent mahogany table on display in the dining room.
Tributes were also paid to Cormac Foley, botanist and former park superintendent for his advice on restoring the gardens.
A former regional manager with the National Parks and Wildlife Service, Mr Dawson said there will be no entry charge for the next few weeks.
Three of the most important public rooms are now open including the drawing room, with antique furnishings including Killarney inlaid furniture, some of which is found in Kensington Palace after being presented to Queen Victoria on her visit to Killarney in 1861.
Meanwhile, a new exhibition centre is to become an interpretive centre for the 25,000-acre Killarney National Park.