FOR 50 YEARS, some of the most influential business leaders and key federal administration figures in town have been quietly committing financial power and expertise to major improvements in the fabric of greater Washington. The Federal City Council, founded by Philip L. Graham, then publisher of this newspaper, has worked to develop and strengthen public support for projects to make Washington, in his words, "a more balanced community in the best democratic tradition." Then as now, the needs of the city required behind-the-scenes resources of civic-minded business leaders who could enlist Congress, the White House and local officials to make things happen. In turn, the success of the council's efforts was to hinge on the choice of a point person with the vision, negotiating style and knowledge to command respect and seal deals.

Only two executives have served in that capacity. The late G. Yates Cook, a nationally recognized housing expert, was executive vice president for 20 years. Kenneth R. Sparks, who had served as Mr. Cook's able deputy, then moved smoothly into the job. Now he has just retired after a remarkable run.

During his 30 years in the post, Mr. Sparks was a guiding force in negotiating countless complex projects, including the Ronald Reagan Building and International Trade Center, MCI Center and the renovation of Union Station. In addition to these bricks-and-mortar additions to downtown, Mr. Sparks expanded the council's efforts to improve public education, to combat drug abuse, to strengthen the District's financial posture and to press for more local governance.

Mr. Sparks embraced the city and his missions with gusto, gliding from project to project, bringing federal and local powers together, diversifying the council's membership -- all with a soft hand, a good ear and a gentle perseverance. "Ken has that remarkable style of getting people to work together," says Council Chairman Terence C. Golden, "and of asking questions in a way so that everybody feels they're participating." Council member R. Robert Linowes notes that Mr. Sparks "doesn't put on a big show, and he takes the time to do things right."

Now he will be taking some time to pursue his pet council project, a downtown museum devoted to music. With quiet might and modesty, Ken Sparks has played a huge role in the betterment of Washington; we suspect that he is not done yet, which is a comforting thought.