Burtell M. Jefferson, a soft-spoken, no-nonsense police commander who is known as both a stern disciplinarian and a progressive, community-minded administrator, was named yesterday as the District of Columbia's next police chief, the first black to head the 4,100 member force.

Jefferson, 52, took over as the Washington police department's acting chief yesterday, immediately after his appointment was announced by Mayor Walter E. Washington. He will become chief officially when the current chief, Maurice J. Cullinane, retires because of medical disability, probably on Jan. 31. Jefferson, a 29-year police "veteran, had long been viewed as Cullinane's [WORD ILLEGIBLE] apparent.

Jefferson's selection was viewed as a skillful political move by the mayor. Jefferson appeared likely to provide at [WORDS ILLEGIBLE] symbolic and psychological brought black police office and official who now comprised about 45 per cent of the city's police force. As several policemen noted yesterday, failure to name Jefferson as Cullinane's successor would likely have caused dismay among many black police officers.

Jefferson announced no major changes in the police department and said he plans to continue Cullinane's overall policies. As assisstant chief in charge of field operations, Jefferson has held the department's No. 2 position and served as Cullinane's righthand man, overseeing day-to-day operations.

In news conferences and interviews, both Jefferson and Cullinane stressed the department's nuts-and-bolts mission, saying that their main achievement in recent years and primary aim in the future were to reduce crime. Crime reported in the city, they noted, has already declined for 22 consecutive months.

In selecting Jefferson, Mayor Washington appeared to have left his prospective rivals in the 1978 mayoral election little room for political attack. D.C. City Council Chairman Sterling Tucker praised Jefferson, saying, "He would have been my choice."

At-large Council member Marion Barry expressed slightly more lukewarm approval. "I'm glad that Jefferson was the mayor's choice," Barry said, but he added that he might not have made the same choice if he himself were mayor. Neither Barry nor Tucker has formally announced his candidacy, nor has Washington announced yet whether he will seek re-election.

Cullinane, 45, did not disclose what he will do after he retires, and attributed his decision to step down after three years as chief primarily to what he described as an increasingly severe knee injury. "No chief of police can take it easy as my doctors want me to and still run a good department," Cullinane said at a news conference.

His injury, he recalled, stems from an incident in 1968 when a brick thrown by an antiwar demonstrator struck him in his left knee. He said his knee ailment has in recent years led to a circulatory problem in his leg, and added that his doctors have told him that he should undergo surgery because he needs what he termed a new kneecap.

Cullinane is expected to receive a tax-free pension of about $31,600 a year as a result of his medical disability. He is scheduled to appear Thursday before the city's Police and Fire Retirement and Relief Board.

If the board approves his disability pension, as expected, he will be eligible to receive the $31,600 tax-free pension, which is 66 2/3 per cent of his recent yearly salary of about $47,500. If the board disapprove the disability, he will be entitled to a pension equal to 59 per cent of his salary, which would be subject to local and federal taxes.

Cullinane, who has already, according to police officials, cleaned out his office at police headquarters, could not be reached later in the day to discuss his financial status. Nevertheless, the tax-free pension he is expected to receive appears to be only slightly less than his after-tax earnings as police chief. By one tax analyst's estimate yesterday, Cullinane's after-tax income as chief seemed likely to be about $35,000 a year.

Some officials and observers noted yesterday that the selection of the city's first black police chief now carried less significance than such an appointment would have had during the racial turmoil of the 1960s and early 1970s.

Mayor Washington and Councilman Tucker both said Jefferson's race was unimportant. Council member Barry argued that the police cheif's race in itself was less significant than the number of blacks serving in other upper-echelon positions in the police department. Barry contends that there are still too few black police officials in the middle and upper ranks.

Nevertheless, it was clear that the choice of a black chief was welcomed by some black members of the police force. One middle-ranking black policeman termed it "a significant, positive step" that may result in greater sensitivity to racial issues within the police department. "I don't think we're past the racial issues," he added, in firm disagreement with earlier assertions by top city officials.

Although Jefferson is regarded in police circles as a progressive administrator, he has not gained a reputation for innovation. He is expected to carry out policies that were begun by former Police Chief Jerry V. Wilson and pursued by Cullinane, Wilson's successor, rather than seking immediate, major shifts in the department himself.

Wilson, who was police chief from 1969 to 1974, undertook an expansion and modernization of the police force and won praise for slowing the rise of crime here, improving police-community relations, hiring more blacks and women and containing protest demonstrations.

In a telephone interview yesterday, Wilson, who has since written extensively about law enforcement affairs and is president of a private security firm, stressed, however, that much has changed in the police world in recent years. Such issues as recruitment of blacks, community relations and innovative planning have faded in importance among police administrators, he said. "Those kinds of issues are gone."

Wilson said he had high regard for Jefferson and expected him to be a "good chief," especially in the belt-tightening era of the 1970s. "What you need is a good, solid, reliable person, and Jefferson is that," Wilson said.