Reyes-Gavilan speaks to Mayor Vincent C. Gray in the Great Hall of the MLK Library, a building he is tasked with redeveloping. (Photo by Bill O’Leary/The Washington Post)

Richard Reyes-Gavilan, the next chief of the D.C. Public Library, loves big libraries. In his introductory remarks Thursday before Mayor Vincent C. Gray and other dignitaries, he was rhapsodic in describing visits to the central library in his childhood home of Queens, N.Y.

“The dignity that I was afforded when I walked through the revolving doors of that building on Merrick Boulevard every Saturday morning was like nothing I ever experienced,” he said. “Here was a space that made me important. It encouraged my curiosity, it made me a better student, it made me a more civic-minded person.”

In his new job, the 44-year-old Reyes-Gavilan will have the opportunity to revamp the District’s biggest library — the Martin Luther King Jr. Memorial Library — seeing through a planned renovation of the four-decade-old structure designed by modernist icon Ludwig Mies van der Rohe. It stands to be the most crucial part of his job, coming after predecessor Ginnie Cooper presided over the rebuilding or renovation of most of the system’s neighborhood branches.

What Reyes-Gavilan will undertake is just as momentous and complicated in political, financial and administrative terms —  building support, most likely, for a public-private partnership that finances the redevelopment in part by adding floors to the Mies structure, then leasing part of it to a private entity.

“I think we have a real empty canvas,” he said of the MLK plans. “We have to be absolutely respectful of the foundation of this building. Honestly, my first impressions are, this is a spectacular building, so we have to renovate it to deliver 21st century services.”

That’s right: first impressions. Thursday’s unveiling was the first time Reyes-Gavilan had set foot in MLK.

I was expecting something that was going to be a little bit more beat up,” he said. “I’m a big Mies fan. I know that he is not everyone’s favorite, but I certainly like the boxy, functional nature of his work.”

But in his prepared remarks, Reyes-Gavilan acknowledged the concept of a library might have passed the old design by: “When Mies designed this building in the 1960s, libraries were largely transactional in nature,” he said. “You come in, you get a book, you leave. Almost half a century later, libraries aspire to be more than just transactional spaces, they aspire to be transformational. They have the ability to make profound differences in the lives of their users, especially the most vulnerable populations who have few other options for acquiring knowledge.”

Reyes-Gavilan’s toughest challenge, though, might be political, not architectural. Should a deal with a real-estate developer provide the most viable path to renovation, he will have to sell it to skeptical activists wary of any commingling of public and private interests. It’s a clash he is familiar with from his soon-to-be-previous job with the Brooklyn Public Library, which has proposed selling the site of a low-rise branch in downtown Brooklyn to a developer, who would build a high-rise and sell a portion of it back for continued use as a library.

“My message to folks in Brooklyn or Washington or Seattle or anywhere else is that the library’s job is to ensure that the library remains viable and relevant for the users of this system,” Reyes-Gavilan said when asked about public-private deals. “We have to be creative in ways that we can make that happen and if it requires a public-private partnership in one place and not a public-private partnership in another place, that is less of a concern to me as … always deliver[ing] phenomenal library services on behalf of our patrons. I realize that there’s always controversy with any type of public-private partnership but it’s incumbent on me and the board and the staff to keep the mission of the library forefront in any decision that is made on behalf of the building.”

Reyes-Gavilan said he plans to start work in early March.