MORE THAN 23 years ago, Maurice J. Cullinane surprised no one in particular by following his great-uncles and father into the District police department. On Friday, in a brief address to the 4,100-member force that he has commanded for the last three years, Chief Cullinane, 45 announced his plans to retire by the end of January for health reasons. What needs to be said about his record is simple: The police force Mr. Cullinane leaves is a better-equipped, better-trained and more respected group of men and women - and this community is a better place - precisely because of the job he has done. He deserves the community's thanks and praise.

Mayor Washington's choice of Assistant Chief Burtell M. Jefferson to succeed Chief Cullinane is a good one. Mr. Jefferson is also a native Washingtonian who has earned increasing recognition as a community-minded veteran investigator. That the man chosen to be the city's next chief happens to be black is obviously a noteworthy "first." But it is not the basis on which he was chosen nor should it be the standard by which the appointment is judged. Mr. Jefferson was chosen on the basis of a nearly 30-year record of impressive police service that should stand him in good stead. Certainly he inherits one of the city government's best managed departments, thanks largely to the administrative efficiency of Chief Cullinane. The departing chief managed to achieve his goal of resisting any efforts by city office-seekers to politicize the department or use it as a foil for attention in the early years of increased self-government under the charter. He also presided over many innovations in law enforcement here, taking the lead in 1976 in helping to create a joint police-U.S. attorney's office "career criminal unit" to weed out recidivists and put them behind bars while they were awaiting trial. Chief Cullinane also encouraged and personally supervised the celebrated Sting and successor operations with the FBI, as well as other important efforts to coordinate interagency law enforcement programs.

Above all, Maurice Cullinane has consistently demonstrated a sensitivity to the needs and feelings of his officers and the people they serve and protect. It paid off through an era of remarkably good police-community relations in this city. In wishing him well for the future, we like to think that Washington and the nation will continue to benefit from his expertise and good counsel.