The Prince George's County Council yesterday unanimously appointed Maj. Michael J. Flaherty to head the county's 900-member police force after an hour-long public hearing in which the local NAACP rated him "not objectionable" as a chief.

Flaherty, whose backing from the community was considered a key factor in his appointment, pledged to improve relations between the police force and citizens by attending more community meetings, being more accessible to them and encouraging the department's leadership to do the same.

He also said he would be devoting the next few weeks to reorganizing the department's leadership and upgrading its crime prevention efforts.

While the backing of the local NAACP was merely lukewarm--the "not objectionable" rating it awarded on what it called its "report card" was lower than two other possible ratings--a spokesman for the group said in a statement that Flaherty would be "a chief with whom we can work to improve opportunities for black employes as well as to improve the effectiveness of law enforcement services countywide."

Flaherty, 40, a 17-year-veteran of the force, said good naturedly after the hearing that "I pride myself on my performance. I've been on honor rolls throughout my career and that's the lowest report card I ever had. But I passed; that's the important thing."

Flaherty, who was sworn in yesterday, will be paid $53,000 a year--an $11,000 increase from his previous salary as a major on the force.

County Executive Parris Glendening nominated Flaherty in August, ending months of speculation over who would replace Chief John E. McHale.

Many police officers had expected Glendening to nominate Lt. Col. Joseph Vasco, a former acting police chief who was supported by the leadership of the county's Fraternal Order of Police.

Vasco's nomination was opposed by the NAACP and several black community leaders because of his alleged involvement in a 1967 series of stakeouts of local stores. Vasco was accused of helping informants set up robberies in which two suspects were killed by waiting police.

Although Vasco was repeatedly cleared of any wrongdoing, Glendening said that the remaining "negative perceptions" about him would hinder his effectiveness as chief.

This week Vasco received permission to retire on medical disability stemming from an old injury in an automobile crash; he will end his 20-year career on Friday.

In response to questioning by County Council members yesterday, Flaherty said he plans to address the complaints of black police officers who want improved promotional opportunities for minorities. He said an informal task force has already begun to investigate the issues and will report within 30 days.

Dozens of law enforcement officers turned out yesterday to support Flaherty, including McHale and his predecessor as chief, John W. Rhoads, and several municipal police chiefs.

Conspicuous in their silence were the past and current FOP presidents, who were present but did not testify at the hearing.

FOP president Mahlon Curran had said earlier that his group considered Flaherty the "second-best choice."

Yesterday Curran said, "I'm trying to think of something to say. I'm just indifferent as heck to the guy."