Democrat Rose Krasnow is running for Montgomery County executive. (N/A/Krasnow campaign)

A fifth Democrat has entered the wide-open race for Montgomery County executive — Rose Krasnow, deputy director of the county's planning department and a former three-term mayor of Rockville.

Krasnow, 66, filed a notice of intent to run under the county's public financing program on Friday and plans to formally announce her candidacy to lead Maryland's largest jurisdiction on Thursday.

She is the first woman to enter the race to succeed three-term incumbent Isiah Leggett (D), who is retiring at the end of next year, and she would be the first female county executive since the position was created five decades ago.

Krasnow, a 37-year resident of Rockville, said she brings executive experience and geographic diversity to a Democratic primary race whose other candidates — state Del. C. William Frick and term-
limited County Council members George L. Leventhal (At Large), Marc Elrich (At Large) and Roger Berliner ­(Potomac-Bethesda) — live in more affluent and educated parts of Mongtomery County, including Bethesda and Takoma Park.

She described Rockville, Germantown and Clarksburg as home to large pockets of ethnic diversity "that I sometimes feel like aren't being heard," particularly given consistently strong voter turnout further downcounty.

"I really do feel that people are looking for a new voice," Krasnow said. "The fact that three incumbent council members are running — to me, that doesn't represent a new voice."

Robin Ficker, of Boyds, is the only Republican in the race so far. Potomac businessman David Blair is expected to announce his candidacy for the Democratic primary soon. The filing deadline is in February, and the primary is June 26.

Krasnow spent three terms as Rockville mayor from 1995 to 2001 after two terms on the Rockville City Council. She led efforts to redevelop downtown through creation of the bustling Rockville Town Center and obtained approvals for the King Farm and Fallsgrove subdivisions.

She will leave her position at the planning department at the end of this year to focus on her campaign.

Krasnow said she decided to participate in the county's new public financing system, which prohibits corporate or PAC donations as well as individual donations above $150, so she could better reach voters and push back on any critics who might use her record as mayor and with the planning office to label her as "in the developers' pockets."

Among her Democratic opponents, Elrich and Leventhal are seeking matching funds; Berliner and Frick are not. Ficker is seeking matching funds.

Krasnow described an "age-old struggle" between supporters of "slow growth" and "pro-growth," saying Montgomery needs to attract businesses to expand the tax base and avoid residential property tax increases, such as the 9 percent hike the council approved last year.

" 'No growth' does not help this county. I think it takes it in the wrong direction," Krasnow said.

Krasnow is the president of Montgomery Women, which aims to help elect women to positions of leadership. "I am well aware of the need to get women at the table," she said.

She's been endorsed by council member Nancy Floreen (D-At Large), the first sitting county lawmaker to make an endorsement in the race. "She doesn't pull ­punches," Floreen said. "She's not going to say things just to make you happy. She's going to speak the truth."