The Arlington County board yesterday named Anton S. Gardner as county manager. Gardner, who has been serving in the post on an interim basis for three months, takes over a county that is fiscally sound but faces a decline in moderate-cost housing and an overhaul of pay scales for county employes.

In announcing his unanimous selection, board members praised Gardner's familiarity with Arlington, his fiscal expertise and his persistence as a problem-solver.

Gardner, 42, has been a county employe since 1971. "He's an Arlington product," said board member Ellen M. Bozman.

The board set Gardner's salary at $85,000 a year. He will supervise a work force of about 2,800 and oversee a budget of $319.2 million. He replaces Larry J. Brown, who resigned in April to take a similar position in rapidly expanding Hillsborough County, Fla.

Gardner said he was "pleased, excited and honored . . . to be affiliated with a government genuinely committed to providing excellent county services."

He said his immediate priorities will be to complete projects. These include a study that will recommend changes in the classification and pay scales of the county work force and a county-led proposal to have a nonprofit group buy a section of the Lee Gardens apartment complex to preserve it as moderate-cost housing.

Gardner said his long-term goals are to "enhance neighborhoods, improve services and ensure an adequate supply of affordable housing."

A native of Queens, N.Y., Gardner started in 1971 as an administrative aide to the county manager. He has served as the director of the Department of Management and Finance and has been deputy county manager since 1983.

His job as the county's chief fiscal officer often placed Gardner in the adversarial role of disputing budgets submitted by other departments.

"His style was intellectual and questioning," said a department head who declined to be quoted by name. "He's not at all bashful about saying no."

As deputy county manager, Gardner showed a more collegial style, and his questions now concentrate on the long-range implications of proposals, say some county officials.

"Now he says, 'Is that enough?,' " said the department head.

Gardner has been the county's chief negotiator in the development of major projects such as the Ballston Common shopping center and the Court House Plaza, which is under construction.

Gardner "has demonstrated an extraordinary capacity for achieving success on such complex issues," said board Chairman Albert C. Eisenberg.

In conducting the search for a manager, the board spent about $30,000 and interviewed five professionals culled from a group of 85 candidates from around the country, said board vice chairman John G. Milliken. In the end, the board found Gardner to be a "compelling combination of a thorough professional and a home town boy."

Board member Michael E. Brunner also noted Gardner's roots in Arlington. "He is not a rolling stone. I don't see him using this as a four-year steppingstone to something else," said Brunner, referring to Brown's departure.

In other action yesterday, the board denied a request to rezone to commercial two adjoining properties on Lee Highway after more than 25 nearby residents protested. But the board, noting that the county's land use plan allows commercial use of the properties, set up a task force to devise a compromise between the neighbors and the property owner.

Also, the board unanimously approved the $44 million Quincy Street Station development in the Ballston area. The project by the John G. Shooshan Co. includes an office building and 202 apartments on North Fairfax Drive bounded by north Randolph and Quincy streets.