Michael E. Shapiro, the crowd-pleasing director who presided over two decades of explosive growth at the High Museum, announced Wednesday he would be stepping down.

“I think, after 20 years, why not give someone else a shot to take it to the next level?” said Shapiro, in an exclusive interview with The Atlanta Journal-Constitution.

Shapiro will leave the High on July 31, 2015, as he completes his 20th year guiding the museum, first as deputy director, then as director.

It has been a time of momentous change at the Midtown cultural center.

During Shapiro’s tenure, the High constructed a three-building expansion designed by Italian architect Renzo Piano, more than doubling the facility’s footprint.

The museum also stepped up its acquisitions, almost doubling its permanent collection, and adding the works of some artists, including Ellsworth Kelly and Alex Katz, by the roomful.

But Shapiro's most notable influence was in the High's collaborations with museums in Europe and Asia, through which he organized exhibitions of blockbuster traveling shows, some featuring works never before seen in the U.S.

The most ambitious of these was the High’s ongoing relationship with the Louvre, which brought nearly 500 works of art from Paris to Atlanta between 2006 and 2009. The first year of the “Louvre Atlanta” partnership attracted 397,000 visitors to the museum, the second-highest attendance of any show.

Of those exchanges, Shapiro said, “it was just a relentless march of great visual treats.”

Shapiro will also be remembered for such populist events as this year's "Dream Cars" and 2011's "The Art of Golf," which appealed to mass audiences and stretched the boundaries of fine art to include artifacts of pop culture.

Shapiro, who will turn 65 next year, said there is no pressing concern prompting his decision to step down, nor is there another position at another institution that he seeks.

“I have led, for the last 20 years, a very structured life,” Shapiro said, “so it’s nice to just contemplate some reduction in that.”

He mentions the possibility of doing consulting work — perhaps writing a book — but his plans are pointedly open-ended. “I don’t think that I’m necessarily done doing interesting things,” he said. “I just have no idea what they will happen to be.”

He doesn’t mention the move as a retirement, and the youthful Shapiro, with his smooth skin and thick head of hair, doesn’t seem the retiring type. He spoke at his office on the ground floor of the Piano expansion, where a monumental colorfield painting by Edward Avedisian shared pride of place with a woodcut of Mount Fuji, executed by Shapiro’s daughter when she was in grade school.

According to a press release from the High, the board of directors will conduct an international search for the museum’s next director.

Shapiro's announcement comes at a shaky time for some of the city's arts groups, including the High's sister organization the Atlanta Symphony Orchestra. Both the High and the ASO operate under the aegis of the Woodruff Arts Center. Negotiations between the locked-out ASO musicians and management at the Woodruff are at a stalemate, and in the meantime, the symphony's fall season has crumbled.

This month also marked the demise of the 29-year-old Georgia Shakespeare; two other metro theater companies rang down the curtain in 2012 and 2013.

Yet while the orchestra accumulated deficits, the High continued to operate in the black — for 21 consecutive years, according to Shapiro — despite such expensive projects as the $164 million Piano expansion.

Though the High and the ASO are both part of the Woodruff, each division must be responsible for its own success, Shapiro said, a philosophy borrowed from Harvard University and colloquially called “Every tub on its own bottom.”

Shapiro earned a Ph.D. at Harvard, before teaching at Duke University and serving at museums in St. Louis and Los Angeles. He became deputy director at the High in 1995 and director in 2000.

Attendance at the museum has waxed and waned, often swelling during the most popular traveling shows, such as 2009’s terra cotta warrior exhibition, “The First Emperor.” That display drew 400,000 customers, a mark the High has yet to match.

During Shapiro’s first decade, the High’s emphasis on art from elsewhere disgruntled some members of Atlanta’s arts community, a complaint that Shapiro concedes is legitimate. Yet his goal, he said, was to bring the best art in the world to Atlanta. “That does not necessarily exclude nurturing the local and regional ecology, but the fact is we need to cast our net as broadly as possible.”

While casting his net, Shapiro has carefully nurtured personal relationships, practicing the art of "showing up," so that the directors of the Mauritshuis in the Netherlands became accustomed to his visits. Ten years of "showing up" paid off, and Shapiro eventually talked the gallery into lending the Vermeer masterpiece "Girl With a Pearl Earring," along with a handful of other great Dutch works.

He also leverages the power of the handwritten thank-you note. In his office is correspondence from Henri Loyrette, the former director of the Louvre, who includes a hand-drawn map showing the way to the Parisian’s home, where Shapiro is invited to visit.

“I learned,” said Shapiro, “a handwritten note works wonders.”