High above Pennsylvania Avenue, in a massive, ornate office built originally for the city's federal overseers, sits Kelvin J. Robinson, chief of staff to the mayor and the administration's designated bad cop.

Brash, dapper and private, Robinson, 41, is little loved and little understood in the John A. Wilson Building. Veteran D.C. Council member Sharon Ambrose (D-Ward 6) said simply, "I don't know what Kelvin does, I truly don't."

Here's a glimpse: When Mayor Anthony A. Williams (D) was left off the guest list for the State of the Union address, Robinson got the mayor a belated invitation to the first lady's box. He ran the mayor's successful campaign for a top job with the National League of Cities. And last month, when it came time to show the door to Lawrence Hemphill, the Cabinet official whose wife was at the center of the Washington Teachers' Union scandal, the job fell to Robinson.

But protecting the mayor and his administration from the stain spreading from that scandal is proving far more difficult than simply pushing out Hemphill. In the last month, Williams has seemed buffeted by events rather than in command of them. And in the latest allegations, Robinson has not been a dispassionate strategist plotting the mayor a safe course through ethical troubles; he has been a subject of the accusations.

Among the questions are whether he violated city and federal ethics rules by attending a $20,000 party thrown for him by the teachers union. Federal investigators and the city's Office of Campaign Finance are looking into the event. He has denied wrongdoing and said he didn't know the union paid the bill.

The developments have turned a harsh spotlight on Robinson, who prefers to operate beyond the public eye. They also have prompted no small amount of gloating among his legions of detractors.

Eighteen months after arriving from Florida with no experience in municipal government and no knowledge of D.C. politics, he is regarded by many in the city's political community -- even by some of the mayor's own advisers -- as a neophyte, undeserving of both his apartment-size office and his unmistakable swagger.

Yet Robinson's style hasn't alienated his most crucial ally: Williams. "Kelvin's doing a superb job for me," he said. "When you're chief of staff, you're not Mr. Congeniality. . . . Your job is to make the trains run on time."

Williams and other senior administration officials credit Robinson with bringing order to a chaotic mayor's office. When he arrived in August 2001, Williams had not had a permanent chief of staff for several months, since the departure of his longtime friend Abdusalam Omer, who was eased out because of his role in a scandal over improper fundraising in the mayor's office.

Robinson reorganized the office, enforced a new level of discipline and took an active role in personnel decisions, filling several jobs with personal associates, including former colleagues from the League of Cities.

He has clarified the office's legislative agenda and pushed the mayor's priorities in countless meetings almost every week. Such bureaucratic basics as paper flow and decision-making are demonstrably improved under his leadership, officials say.

But several sources close to the mayor say Robinson's inexperience has shown in the administration's mostly passive response to the teachers union scandal. A savvier operator, they suggest, would have probed the administration's connections to the union ahead of reporters and investigators.

Robinson defended his approach in a recent interview, saying the administration must stay focused on its goals and also tread carefully as long as there are criminal investigations into misdeeds by former union officials.

"There are a lot of folks who want us to be distracted by it, but we're really not," he said. "We haven't spent a lot of time sitting here thinking, 'Oh, who paid for the potato chips?' "

Some of these critics also knocked his handling of the nominating petition scandal last summer. Among their concerns was Robinson's suggestion that Williams run as an independent after he was denied a spot on the Democratic primary ballot. The mayor rejected that idea, following the advice of those who contended that it would be politically dangerous to abandon the nomination to potential challengers in a city with an 11-to-1 Democratic edge.

Robinson declined to comment on his advice to the mayor, but he acknowledged the difficulty of taking such a prominent job in a new city, and he said he's not surprised that his aggressive management style has struck many as brusque.

"I don't do a lot of chitchat with folks most of the time, and I stay focused on the things we're going to do," he said. "I'm going to give 110 percent, and I'm going to expect that from everyone else. And some people aren't used to that. . . . Maybe my standards for some are too high."

Collegiality has never been his strength. The Fort Lauderdale, Fla., native used a combination of perfectionism, drive and hard work to rise through that state's governments.

One of those jobs was heading up Florida's fledgling -- and since abandoned -- auto emissions testing program as the first African American bureau chief in a highway department dominated by middle-aged white men. "Sometimes he got a little full of himself," recalled his former boss, department Executive Director Fred O. Dickinson III, "but he ran a good shop. There was no scandal."

Robinson eventually became a lobbyist with the Florida League of Cities, where he stayed for several years before resigning over an incident in which he was accused of having two subordinates write personal checks to pay for a bonus for a fellow employee -- against the wishes of Robinson's boss.

In that job, he also spent time in Washington working for a Florida mayor, Clarence Anthony, when he was president of the National League of Cities. It was Anthony who introduced Robinson to Williams, who aspired to head the group -- and is on track to do that thanks in part to Robinson's connections.

"People who are not used to such a demanding, workaholic, perfectionist boss as Kelvin would clearly find him a difficult person to work for," said Anthony, mayor of South Bay, Fla. But he said that Robinson's tough and polished exterior hides a private side that is more relaxed and gentle.

And with Mayor Williams's approval secure, Robinson made clear that he has no intention of altering his style to appease his critics. Nor does he plan to change offices, despite much griping about the extravagance of his work space. "Somebody's got to sit here," Robinson said. "Might as well be me."

Kelvin J. Robinson has become the focus of accusations in the teachers union scandal.