Fabian Barnes, who was founder and director of the Dance Institute of Washington, is shown in 2006. Barnes died unexpectedly Friday at 56. (Bill O’Leary/The Washington Post)

The Dance Institute of Washington is reeling from the unexpected death Friday of its founder and director Fabian Barnes, 56, the hard-driving and big-hearted former Dance Theatre of Harlem soloist who devoted his life to training underprivileged children in classical ballet.

Barnes had been sick for some time, though no one knew the details, said Jared Fischer, a longtime DIW staff member and grant writer.

“Fabian being so private, we can’t even speculate what the illness was,” Fischer said. In recent phone calls, “he’d say things like, ‘I’m not doing well, I’m getting over a sickness,’ and you could hear in his voice he wasn’t doing so hot.” Fischer said Barnes had not been seen at the school since early March.

Marcellous P. Frye Jr., chairman of the DIW board, went to Barnes’s house Friday evening with another board member to check on him. When no one answered the door, they called police. According to the police report, Barnes was discovered in his bedroom, dead of natural causes.

Adding to the mystery and shock of his death is that Barnes was known for his energy and stamina. He was an imposing figure, a tall and powerfully built man who seemed to fill a room when he entered it. In launching his school, he took on two jobs at once, opening up a summer ballet program for underserved children in the District in 1987, while on a seasonal break from the Dance Theatre of Harlem.

Barnes, the youngest of 10 children, grew up poor in Seattle, said Marvin Miller, a DIW board member and close friend of Barnes. “Dance saved his life,” Miller said Tuesday. “It took him somewhere else and gave him a focus. That’s why he was so emphatic about serving children who are at risk, to let them know they had options.”

In the late 1990s, Barnes retired from dancing to teach year-round in circumstances that were far from ideal, relying on rental studios in some of the poorest parts of town. In 2000, he was awarded one of Oprah Winfrey’s “Angel Network” awards, and soon after that he started fundraising to buy a building for his school.

It took five years of meetings and headaches, but in 2006 Barnes opened his institute in a custom-designed, $5 million building, with three dance studios, on what had been an overgrown vacant lot.

“A lot of people here want to do good things, but few are able to achieve so much so quickly,” said Septime Webre, artistic director of the Washington Ballet. At a time when his own institution was trying to expand, he admired Barnes’s know-how. “Pulling off that stunning building in Columbia Heights was pretty amazing. He succeeded where we didn’t in that regard.”

“When he first started, he was so adventurous and so determined,” said Carla Perlo, founder and director of Dance Place. “Fabian right away seized the opportunity. A lot of people wait for the perfect thing, and the perfect thing never arrives. . . . He had to envision and fundraise and build from the bottom up. But he knew he could bring the magic.”

The strain of that effort surprised him, Barnes said in a 2006 interview, when his Columbia Heights building opened: “If I knew then what I know now, it probably would have stopped me” from buying the property, he said. “Not to say I’m not happy I did it, but everything comes with a price. My price was sleepless nights and high blood pressure.”

DIW quickly grew in recognition. In 2011, the school received the National Arts and Humanities Youth Program Award. Enrollment now tops 600 students, said Kahina Haynes, the school director. Nearly 1,000 students typically attend over the summer, she said. DIW graduates have gone on to join such companies as Dance Theatre of Harlem, Alvin Ailey American Dance Theater and the Charlotte Ballet. The professional company Washington Reflections, which Barnes had founded at the Columbia Heights location, is on hiatus.

Barnes had raised the topic of his retirement in recent months, said Frye, suggesting that he might like to step down in a decade or so. “It was nice to see Fabian involved, accepting new ideas and bringing up planning,” Frye said. “He’d said he wanted to mentor somebody to take this on.”

That effort must continue without him; no plans have been made yet to search for a successor, Frye said. He added, “The most important thing that we need to do is to make sure that we continue with the legacy and purpose and mission that Fabian set forth almost 30 years ago.”