Mountaineer George Leigh Mallory blithely noted that he wished to ascend Mt. Everest “because it’s there.”

Nate Levine, however, has opted to step down as executive director of the JCC of San Francisco for much the same reason — after years of hearings, angst, fund-raising and construction, the Jewish Community Center is, indisputably, there (just take the 1 California bus from downtown — you can’t miss it).

But while Everest has been around for millions of years, the JCC’s palatial home wasn’t there until Levine spearheaded an aggressive fund-raising and construction drive.

Levine’s nine-year tenure atop the JCC will be remembered for more than just building a splendid new home — though that is, inescapably, his major legacy. He’s chosen to step down at a moment when the JCC is in the black, thriving programmatically and utilized by more people than Levine and others ever anticipated during the long run-up to construction.

“This center hasn’t accomplished everything. I have said the best is yet to come,” he said.

Levine, 52, had been mulling over his future for several months before coming to a decision earlier this year.

“Anybody who’s an executive director gets calls from headhunters asking if you or someone you know is interested in a job,” he said.

Over the years, he fielded many of these calls, and always quickly dismissed the possibility of new employment. Until recently.

“I got a call two months ago — I don’t even remember what the job was. But if it had been of interest, I would have, for the first time, asked them to tell me more. That was an indication that I’d come to a transition point,” he recalled.

Levine quietly informed JCC board president Bethany Hornthal and Chief Operating Officer Sandee Blechman of his decision and both were shocked — but not surprised.

“My heart stopped. I was sad he was leaving because we’ve had such an unbelievable partnership. But I also knew this was the opportunity I had been waiting for,” said Blechman, the JCC’s COO since 1997 and Levine’s successor as executive director.

Hornthal said she’d been anticipating such a move from Levine. “Nate had set up what we refer to as a BHAG — a Big, Hairy, Audacious Goal. We had to create a BHAG for Nate, which was to build the center,” she said.

“Nate accomplished that, and not just by stopping off with the building but by being here for the next couple of years and seeing we had financial stability, community and particularly the infrastructure and strong management team. It makes perfect sense that Nate will go and climb his next mountain.”

Levine defers much of the credit for the JCC’s turnaround to others, but it’s hard to ignore the before and after of his tenure.

At the onset, Levine realized that if he kept up the status quo, the JCC would exhaust a roughly $2 million line of credit within about a year. He reversed a policy of reacting to dwindling income by cutting programming, a move that had induced a downward spiral in attendance and revenue.

The turning point for the center seemed to be the decision to lease out its fitness facility to Club One, becoming the first JCC in the nation to enter into such an agreement with a for-profit outside entity. Membership soared and, at the present time, 5,000 people visit the center every day.

Levine stressed that fund-raising was always a “means and not an end.” But prior to the last fund-raising drive, the JCC had fewer than a dozen donors who’d given gifts of $100,000 or more. In order to build the new center, Levine and his staff convinced 29 people to give between $1 million and $10 million.

Blechman secured her new post several weeks ago; the JCC announced Levine’s June departure and her promotion Thursday, May 4.

For the longtime COO, it was a dream come true: She’d always wanted to lead a Jewish organization, but didn’t want to leave the JCC.

“I had made my peace with my partnership with Nate even though I’d always felt really eager to take on a leadership role,” she said.

Blechman doesn’t plan any major shake-ups, but does hope to increase collaboration with Jewish and cultural institutions around the city — the upcoming Freud Fest is a major example of that.

She also aims to increase “Jewish values education” at the center for children and adults and better serve as a “gateway” to the organized Jewish community for curious seekers.

Levine is unsure of what, exactly, his next mountain will be. He’s considering taking a job in the foundational world, or opening up his own consulting practice. But he does plan on working out at the JCC gym, just like he always has — “if they’ll have me,” he says with a laugh.