When Anton S. (Tony) Gardner decided to build a house in Arlington six years ago, he first studied a detailed aerial map of the county. He marked out the neighborhoods he was interested in, pinpointed empty lots and methodically contacted their owners until he found one willing to sell.

It was a show of precision and persistence that many say is typical of the man who was appointed in July as Arlington County manager.

Gardner, 43, replaced Larry J. Brown, who resigned to take a similar post in Florida. A former Air Force intelligence officer and an Arlington employe for 17 years, Gardner has served as assistant county manager and head of the county's office of management and finance.

Unlike Brown, who was a newcomer to Arlington, Gardner is familiar with the intricate workings of every county department. He is, by various accounts, an indefatigable worker and a man who has evolved over the years from a narrow technocrat into an open-minded executive.

Gardner is also a fierce negotiator who has driven a hard bargain on development deals, according to some who have worked with him. Part of his success comes from meticulous preparation. He also has one advantage, the knowledge that Arlington can be a mother lode for developers and that builders want the county's good will.

"As county manager he carries a big stick and he is not afraid to wield it," said Daniel R. Mackesey, a vice president of the Artery Organization. "He is a tough negotiator who is willing to play hardball when he feels the circumstances call for it."

Artery and the county recently came to an agreement on the sale of part of the Lee Gardens apartment complex, a bargain that occupied much of Gardner's attention during his first six months as county manager. Artery had planned to renovate the entire 961-unit complex, and the process was expected to displace about 3,000 mostly low-income, mostly Hispanic tenants. The firm offered to set aside some units for low-income residents for several years.

However, Gardner negotiated a deal in which a portion of the complex was sold to a nonprofit housing group that will keep permanently some of the units for affordable housing.

Many thought the deal impossible. Obstacles included the filing by some tenants of a housing discrimination lawsuit, which was later settled; securing federal housing subsidies, and negotiating a record $33.4 million in financing from a state-chartered housing agency.

"I don't believe a sale would have happened without Tony," said Mackesey, Artery's chief negotiator on Lee Gardens. "He has leadership, ingenuity, perseverance, the willingness to take risks."

As assistant county manager, Gardner negotiated two major development deals. One led to the construction of the Ballston Common shopping center.

The other is Court House Plaza, a joint project of Artery and the Charles E. Smith Cos. that calls for residential units, a hotel and a building to house county government offices near the Court House Metro stop.

The county will pay below-market rent for space in one building but retain ownership of all project land and receive part of the rent that the developer collects from tenants in other buildings.

The buildings will revert to county ownership in 75 years.

Gardner "doesn't ask for things that are totally unreasonable but {that are} beyond the pale of what you were prepared to give," said attorney Martin D. Walsh, who represented Artery and Charles E. Smith in the Court House Plaza negotiations. When the talks are over, "you're relieved to get what you didn't want in the first place."

Aside from the Lee Gardens deal, Gardner's first few months in the $85,000-a-year post have been occupied with overseeing a revamping of county job classification and pay scales. "I would have wished for a less hectic first few months, but it's been fine," he said in a recent interview.

He concedes that the reclassification process may cause some staff morale problems. About 200 of the county's approximately 3,400 employes have filed appeals objecting to their new job ranking. Workers whose complaints are not resolved through appeals will "have to come to some reconciliation within themselves," Gardner said.

He added that he has encouraged managers to find ways, aside from pay, to make employes feel valued.

Some who have followed Gardner's career say his style has changed markedly over the years.

Richard A. Barton served on the Arlington School Board from 1978 to 1980. Gardner was then the county's chief fiscal officer and had a single-minded view: the bottom line. "He was very hard-nosed. He knew how to squeeze everything out of a dollar," Barton recalled. "We used to gnash our teeth."

Gardner's view broadened after he became deputy county manager, said Barton, currently head of the county's economic development advisory commission. "He {was} able to reach out and learn more about the community," he said. "I really saw him grow and expand. Before that, he was a good, solid, dependable numbers cruncher."

Gardner said some of the changes in his style stem from successful efforts to strengthen his family life, citing for example, participation in an ecumenical weekend religious retreat designed to improve communications between married couples. He and his wife Linda have been married 21 years, have three teen-age children and live in the Belle View Forest neighborhood.

"I was probably much colder and aloof than I think people would find me now," he said. "I've become more extroverted and sensitive to people and their personal needs and feelings. I'm more flexible and have come to appreciate different ways to achieve the right objective."

Gardner's job performance has so far pleased his bosses, the five members of the Arlington County Board. "I continue to be impressed by his knowledge," said board member Michael E. Brunner. "He's like a machine. You ask a question and out comes the answer. He's not someone who takes 40 minutes to get to the point."

In a county that prizes its placid quality of life, Gardner has been ahead of the curve on controversial issues and has done a good job of keeping County Board members informed. "There have not been any surprises. There have not been any missteps in the handling of major issues," said board Chairman Albert C. Eisenberg.

If the board members have a worry, it is that Gardner, with his encyclopedic knowledge of the county, may become enmeshed in detail. "He will have to pick and choose, with the board's guidance, the issues on which he will spend his time," said board Vice Chairman John G. Milliken, who will take over as chairman Jan. 1.

Gardner is just now beginning to impose his organizational style on his office. He has eliminated his old job of deputy manager in favor of three top assistants.

He is also preparing next year's budget, a document that will emphasize needs such as low-cost housing.

While Arlington is generally regarded as providing good services, Gardner said he wants to emphasize the manner in which county employes deal with residents.

"We get some criticism, not much, about the way people are treated in the process. The thing I'm trying to get across . . . is the way things are done is as important as the things that are done," he said.