Robert Cane, the executive director of an influential pro-charter school advocacy group in the District, has announced he is leaving his job after more than 16 years.

During his tenure at Friends of Choice in Urban Schools (FOCUS), charter school enrollment in the city has grown more than tenfold, from about 3,600 to more than 38,000, representing 44 percent of public school students in the city.

“It’s very hard for me to leave the charter school movement . . . to step out of the role I have had for so long. I’m so committed to what we have done here,” Cane said.

But the 67-year-old former West Coast lawyer said he plans to move to Nevada to be close to his extended family.

Scott Pearson, executive director of the D.C. Public Charter School Board, called Cane a “fierce advocate” who has been “invaluable to the growth and strength of the charter school movement in D.C.”

Robert Cane. ( Alejandra Maudet )

Cane switched careers when he moved from San Diego to Virginia with his family in 1990. He went to the Curry School of Education, then worked as an assistant principal or principal in three traditional public schools.

“I concluded that real school reform for poor kids was not going to happen in public school systems” he said. He took interest in the young charter school movement in the District. In 1998, two years after the School Reform Act made way for the creation of charter schools, he became the first executive director of FOCUS, a fledgling organization with one other staff member.

Cane recalled that many of the early battles for charter schools, like the current ones, were about funding.

“We think we have it bad now . . . but back then it was ridiculous,” he said. He recalled that charter schools often needed short-term loans because the city’s payments were low, and they were at risk of closing. (FOCUS now is supporting a lawsuit waged by dozens of charter schools that is seeking to equalize public funding dollar-for-dollar with traditional charter schools.)

The organization offered training to new and aspiring charter leaders. Mary Procter, the founding chief of staff at Friendship Public Charter School, said she “lived” at the FOCUS office because it offered workshops about real estate and special education or finance.

With Cane at the head, FOCUS has also played a prominent advocacy role.

Cane can usually be counted on to oppose any policies that could infringe on the independence of charter schools, which are publicly funded but given greater autonomy by the law.

He recently spoke out against a bill sponsored by D.C. Council member David Grosso (I-At Large), the new Education Committee chairman, that would ban suspensions and expulsions for pre-school students, except in extreme circumstances.

“He’s a little mellower now in his manner, but his belief is still strong that charter schools are really important and their autonomy is really important,” said Procter, who is now a member of the FOCUS board of directors. “He fights back.”

Cane spoke before the D.C. Council’s Education Committee at an oversight hearing on Wednesday, describing some of the charter movement’s successes.

In an interview, he said Grosso is the fourth or fifth new education chair that he has worked with. “There is a tendency, regardless of who is the chair, to want to come in and pass laws and increase regulation,” he said. “We are keeping watch.”

The FOCUS board of directors is launching a search this week to find a new executive director. Cane said he will stay until they find someone, and he plans to remain as an adviser at least through 2015. “I am not disappearing,” he said.