“It saves a national treasure and meets our medical needs,” said State Assemblywoman Donna A. Lupardo, who helped secure the first part of $38.8 million in state financing for renovations.

When the castle was built, doctors were experimenting with new treatments for alcoholism, approaching it as a disease rather than as an addictive behavior. The first patients here were primarily wealthy, and the castle had a country club reputation, according to Mr. Luther, who has researched its history.

As the treatment program fell out of favor, the state converted the castle into a psychiatric hospital. It was a beautiful backdrop for sometimes harrowing experiences.

“In some ways, the treatments were kind of barbaric,” said Richard L. Diffenbach, 68, who worked there as an aide among violent patients in the late 1950s.

Among the practices were electroshock therapy and “hydrotherapy” — which he described as the tight wrapping of troublesome patients in layers of wet and dry towels or sheets. But the hydrotherapy was stopped in 1959 after a patient struggled against the restraints until he died of a brain hemorrhage, Mr. Diffenbach said.

Other experiences were less painful to recall, including that of a patient who insisted on being called “ZZZ Wafe Rainmaker Father Mother Simon Joseph Frances Carl.” He would sit in a chair in a hallway, shuffling his feet continuously. Today, the grooves that he wore into the wooden floorboards are still visible. “These people are encased in my memory,” Mr. Diffenbach said.

As psychiatric practices evolved, the castle was renamed several times, finally becoming the Binghamton Psychiatric Center. The number of patients at the site began to decline in the 1960s, and by the 1990s many of the psychiatric patients there were deinstitutionalized, as were many other such patients around the country.

By the time part of the facade collapsed in 1993, the building was being used only for office space; later that year, it was closed.

In 1996, the castle was included on the National and State Registers of Historic Places, and the next year it was named a National Historic Landmark.

Options for its future appeared slim; few developers wanted an 85,000-square-foot used castle. When Assemblywoman Lupardo took office in 2005, one of her first visitors was Mr. Luther, who lent her four framed photographs of the building, “to remind me” to make it a priority, she said.

But it was perhaps synchronicity more than lobbying that saved the building. Dr. David Smith, president of SUNY Upstate Medical University, was visiting a health care center at the school’s Binghamton campus when his eyes were also drawn to the castle.

“I thought it would be an incredible home” for a number of projects the university wanted to undertake, Dr. Smith said.

After some negotiations, the university made its announcement. The first phase of the building’s restoration will include $12.45 million in exterior work. Next year, the state plans to tackle $22.85 million in interior renovation. Eventually, the state would like to reconstruct the turrets, which would add $3.5 million.

“It’s architecturally superb,” said John G. Waite, an architect who is in charge of the reconstruction. “It’s more like a resort hotel than an asylum.”