Montgomery County Executive Charles W. Gilchrist appointed his first new department head in two months yesterday, beginning a round of high-level appointments of the people who will shape the slowly emerging policies of his new administration.

Gilchrist named Clinton Hilliard, director personnel for the San Jose, Calif., city government for five years, as the new personnel director for the county.

Hilliard, whom Gilchrist said would "work for, not against, the employes," is the second black to be named by the new executive to a top-level government post.

There has been a two-month hiatus in the formation of Gilchrist's 22-member cabinet, largely because of preparations of the 1980 budget which was preseted to the County Council yesterday.

But the new executive also adopted a cautious course of personnel changes after two of his initial decisions -- the firing of the former police chief and the unsuccessful attempt to transfer the county's lobbyist to a lower-paying job -- resulted in legal challenges.

More recently, however, when Gilchrist decided to dismiss four other department heads, he quietly informed them of his decision without making any public announcements at first. In one case, he authorized a subordinate to dismiss a department head by telephone to prevent the press from getting wind of it.

This low-key style was both praised for its "humaneness" and ridiculed for its "ineptness," and, it gave an indication of how the new executive intends to manage government business.

"I just hate this part of my job," Gilchrist, a lawyer and former state senator, said shortly after the dismissals were completed. "It was a difficult thing to do. They were professional people and I wanted to talk to each one and leave it up to them how they wanted to handle it."

Gilchrist's style won no admirers among the friends of Neil Ofsthun recreation director who balked when they heard that Ofsthun, who worked for Rockville and Montgomery governments for 18 years, was fired over the telephone by Gilchrist's chief adminstrative officer Robert Wilson.

"If a department head has built up a good department and then gets a phone call after 18 years of service, there must be a better way to handle it," said a director of another agency.

Wilosn told Ofsthun he was being terminated in that fashion to give him a chance to make other arrangements quietly. Gilchrist dismissed threeother department heads after summoning them to his office, but other government employes and some reporters heard about what was happening soon afterwards.

Ofsthun, who said it was "quite a blow," added he was "stunned" by the call.

"Based on my record, I had absolute confidence that I would stay," he said. "I just think they must want to gove this job to one of their own people."

Gilchrist was uncharcteristically angry last month when the charges began circulating that he was dismissing agency heads, -- who hold the only jobs among 5,300 which he has the power to fill himself -- to reward political supporters.

"Somehow there's an assumption that I'm throwing out asll these people to make room for political friends," he said. "A person happens to be a friend, poor fella, and that makes him a 'crony.' There will however, be a few cases in which an appointee is a friend."

Defending Gilchrist, Democratic Party Chairman Stan Gildenhorn said he thought the new executive was "acting with courtesy."

"I don't think people are the least bit surprised that the changes are coming, but rather than sweeping into office with rash personnel decisions, Gilchrist took a period of time to get to know his government," Gildenhorn said.

Gilchrist's choice of Hilliard, a Californian, for personnel director was recommended by Robert Wilson, the career public administrator who was the county executive's first appointment after his inauguration last Dec. 4.

Gilchrist said that Hilliard, who holds a masters degree in public administration form the University of California at Berkeley, will "work as much for the emploves as for management" and "end" the adversary role the personnel department occasionally has played in the past.

Employe leaders in San Jose yesterday descirbed Hilliard as "fair," "equitable" and approachable to competing groups in the government.

Hilliard's appointment leaves Gilchrist with eight vacancies to fill including the directors of the Environmental Protection, Transportation, and Corrections Departments. This week Gilchrist telephoned the rest of the department heads to notify them he had decided to keep them.

Aside from Wilson, Gilchrist has already appointed Paul McGuckian, former counsel to the countys legislayive delegation, as county attorney, and Blair Lee IV, son of the former acting governor, as the county's lobbyist in Annapolis.