Democrat David Blair is running for Montgomery County County Executive. (N/A/Friends of David Blair)

The race for Montgomery County executive got a bit wider Sunday with Potomac businessman David Blair launching his campaign for the Democratic nomination, bringing to six the number of candidates seeking to succeed longtime incumbent Isiah Leggett (D).

Blair, 48, is a lifelong county resident and executive chairman of Accountable Health , which invests in and starts technology-enabled health-care companies. A self-described "pro-growth" candidate, Blair is making his first run for public office and hopes to appeal to Montgomery's business community and residents looking for a candidate not on the county's council.

"I get really frustrated thinking, 'Why aren't we the next Silicon Valley?' " Blair said in an interview. He announced his campaign at a small reception Sunday with supporters. "We have great schools, a talented workforce. We have all the assets, so we've got to do a better job attracting businesses here."

The Democrat said he is dismayed by the growing gap between Montgomery's poorest and wealthiest residents and wants to address it by drawing new businesses — and jobs — to boost the economy.

"As I drive around this county, it's becoming divided between the haves and the have-nots," Blair said. "On education, whether it's job opportunities or health outcomes, we're increasingly divided."

Blair is also positioning himself as a "fresh perspective" in contrast with three of his opponents — Marc Elrich (D-At Large), George Leventhal (D-At Large) and Roger Berliner (D-Potomac-Bethesda) — who have held seats on the county's council for years.

State Del. C. William Frick (D-Montgomery) and Rose Krasnow, deputy director of the county's planning department, also are seeking the Democratic nomination. Attorney Robin Ficker is the only Republican in the race with three months to go before the filing deadline. The primary is June 26.

Blair said permitting and other regulations on businesses approved by the council often made it "feel like the business playing field was being tilted away from Montgomery County. . . . I think there's an adverse reaction to the status quo."

Elrich, Leventhal and Krasnow are participating in the county's new public financing system, which offers them matching funds for qualifying small donations. Participants are barred from accepting corporate or PAC contributions.

Blair, a minority partner in Monumental Sports and Entertainment, the parent company of the Washington Wizards, the Capitals and Capital One Arena, said he will not seek public matching funds but will refuse donations from corporations and PACs. He also said he and his wife, Mikel, will contribute to the campaign.

Over the summer, the couple — who have six children — launched Badlands Playspace, an indoor play facility for children in Rockville.

Blair founded Catalyst Health Solutions, a pharmacy benefit management organization, in 1999 and served as chief executive of the company until 2012. He said he has spent the past year divesting from his businesses and will soon relinquish his title at Accountable Health.

His vision for Montgomery, he said, goes beyond comparing the county with its neighboring jurisdictions. "I want to compare ourselves to the best counties in the country," he said. "There's no reason we can't be a leader."