But the gift, the largest monetary donation in the history of New York City’s park system — and possibly the nation’s — was, in a sense, decades in the making. It stretched back to the days when Mr. Paulson, now 56, hung out at the fountain as a teenager, beneath the bronze statue Angel of the Waters, which was then scrawled with graffiti and bone dry. And it took shape more recently on walks with the president of the conservancy, Doug Blonsky, through the park’s North Woods.  The gift comes as Central Park is at a high point, after decades of improvements and restorations — of intricate stone bridges and historic buildings, great lawns and bodies of water — undertaken by the conservancy, the nonprofit group that manages it on behalf of the city, since its formation in 1980. The park, by all accounts, has not looked this good since the landscape architects Frederick Law Olmsted and Calvert Vaux created it in the mid-19th century from an 843-acre rectangle in the center of Manhattan.  But the conservancy’s leaders note that the park’s future success was never assured, citing past periods of decline, particularly the nadir of the 1970s. The $100 million donation should change that.  “The cycles of decline and restoration that this park has suffered for so long will be broken forever,” Mr. Blonsky said in a news conference attended by Mayor Michael R. Bloomberg, as well as past and present parks commissioners and the conservancy’s founders.  The donation should also burnish Mr. Paulson’s image, which has taken some hits in recent years. Mr. Paulson, who has an estimated worth of $11 billion, started his hedge fund, Paulson & Company, in the mid-1990s. He rose to fame and made his fortune in 2007 by betting against subprime mortgages before the housing market collapsed. But he has lost some of his luster lately, suffering steep losses and causing investors to pull some of their money out of his funds.  Mr. Paulson’s financial achievements were also cast in an unflattering light two years ago, when the Securities and Exchange Commission filed a lawsuit against Goldman Sachs that involved a mortgage investment fund that Mr. Paulson had played a role in creating. The lawsuit accused Goldman of failing to tell investors that they were buying into pools of questionable loans. Mr. Paulson was not named in the suit.  He has been on something of a real estate shopping spree. This summer, he paid $49 million for the 125-acre Hala Ranch and adjoining Bear Cabin properties in Aspen, Colo. His primary residence is a 20,000-square-foot town house steps away from Central Park, at Fifth Avenue and 86th Street. Protesters from the Occupy Wall Street movement showed up at that address last year, along with those of other financial titans.  But it was Mr. Paulson’s childhood and family life, particularly as it has intersected with Central Park, that was on display on Tuesday, as city officials turned out to announce the gift, which came jointly from Mr. Paulson and the Paulson Family Foundation. Mayor Bloomberg called the donation “the largest made to any park anywhere” and said it would “benefit the city for years to come.”  After the event, Mr. Paulson strolled out of the park with Mr. Blonsky, and the two discussed how the gift had come about.  Mr. Paulson had been a supporter of the conservancy for years, and he and Mr. Blonsky had taken walks together in the park, but he had never given the group a large gift. In the spring, they began talking about the donation seriously, but the details were not made final until the day before the announcement.  The gift is the latest in a year in which city parks emerged as major beneficiaries of philanthropy, joining more traditional recipients like museums, hospitals and universities. A year ago, the Diller-von Furstenberg Family Foundation pledged $20 million to the High Line, the elevated park on the West Side of Manhattan; that donation followed two other gifts to the High Line from the foundation, totaling $15 million. In April, Joshua P. Rechnitz, an amateur track cyclist, announced a gift of $40 million to Brooklyn Bridge Park to build a field house with a cycling track.  Half of the $100 million donation to Central Park will go toward its $144 million endowment, which helps finance maintenance, while the other half will pay for capital improvements. In his remarks, Mr. Paulson, who runs and rides his bicycle in the park, singled out two projects in particular: restoration of the North Woods, with its waterfalls and scenic paths, and landscaping improvements around Merchant’s Gate in the park’s southwest corner, its busiest entrance.  Nothing in the park will bear Mr. Paulson’s name, which is unusual for a gift of this size.  Mr. Paulson, born and raised in Queens, described his family’s long connection to Central Park: his grandparents had their first date there in the 1920s, his mother was pushed in a baby carriage there, and, later, she took him there in his own carriage as a youngster. He recalled the scruffy 1970s and early ’80s, when the park was in “serious disrepair — its infrastructure was crumbling, its landscape was in shambles and it was plagued with drugs and crime.”  In recent decades, he has watched firsthand the transformation of the park, which has received an infusion of $700 million over 33 years, allowing for top-to-bottom restorations. Most of that was raised privately by the conservancy from residents, corporations and foundations.  Asked what prompted the gift, he said: “Walking through the park in different seasons, it kept coming back that, in my mind, Central Park is the most deserving of all of New York’s cultural institutions. And I wanted the amount to make a difference. The park is very large, and its endowment is relatively small.”  Adrian Benepe, a senior official at the Trust for Public Land who recently stepped down as the city’s parks commissioner, said the gift would help prevent the park’s being loved to death.  “It gets harder and harder to raise operating money,” he said. “The park has 40 million visitors a year, and it’s taking a toll on the landscape. It just can’t keep up with it.”  Mr. Paulson’s donation may have been his first major gift to the conservancy, whose board he joined only in June, but it was not his first act of philanthropy. In 2009, he donated $20 million to the New York University Stern School of Business. That same year, he donated $5 million to the Southampton Hospital on Long Island, which named its emergency department for Mr. Paulson and his wife, Jenny.  And this year, he has been a generous political donor, giving about $1.4 million to Republican candidates, party organizations and “super PACs.” (He also hosted a fund-raiser for Mitt Romney, the Republican nominee for president, in his town house.)  As he left the park, Mr. Paulson deflected questions about his business dealings and philanthropy. He wanted to talk only about Central Park. “I like the park in all the seasons,” he said, as leaves floated toward the ground. “It’s very peaceful when it snows. But you have to wear the right shoes.”  Julie Creswell and Nicholas Confessore contributed reporting.  This article has been revised to reflect the following correction:  An earlier version of this article incorrectly stated that Gordon Davis, a former parks commissioner, was at the news conference. Mr. Davis was not in attendance.  An earlier version of this article incorrectly stated that Gordon Davis, a former parks commissioner, was at the news conference. Mr. Davis was not in attendance.
The hedge fund manager John A. Paulson, who used to frequent the park as a teenager, described his familyâs long connection to it, including a first date there by his grandparents in the 1920s.