On Friday afternoon a week ago, William H. Webster, the FBI director nobody knows, walked into the old U.S. courthouse in Columbus, Ohio, to give a little pep talk to some of his troops.

After half an hour of their first personal contact with the boss, several of the 25 or so special agents assembled said they were impressed. "I was afraid he might be just a 'yes man' for [Attorney General] Griffin Bell," said one. "But he seems to be in command and has an amazing grasp of the bureau for only having been around for a year."

It was on the same afternoon, Feb. 23, one year earlier, that President Carter went to FBI headquarters to swear in Webster for a 10-year term as head of the chief federal law enforcement agency.

On the way 'o Columbus, Webster recalled that moment with Carter. "Everyone there seemed to sense it was a watershed time for the bureau... a time for people to take a new, neutral look... to recognize the importance of the institution," he said.

During the ceremony Webster got his marching orders from the chief executive: no organization in American life has more to do with how the people feel about their government than the FBI. Carter wanted Americans to feel comfortable with the bureau.

That was no small order, of course, for an agency that had been rocked by years of investigations and revelations about spying on citizens But areview of Webste's first year in office shows that the low-profile ex-judge from Missouri seems to have firmly taken control of the FBI.

The anniversary trip to Columbus itself was symbclic. Webster was selling the FBI -- in a news conference, a luncheon with newspaper executives, a speech to an exclusive club of attorneys and professors.

He also was selling himself to a small number of the 8,000 special agents and 12,000 support people he leads.

The 54-year-old Republican judge from St. Louis is the most low-key salesman imaginable. A lot of people in Washington, a most personality-conscious city, still say "William H. Who?"

Webster's style is deliberately understated. In dress -- write or striped button-down shirts and striped ties and herringbone or dark suits with cuffs -- and in conversation and background, he's conservative.

His confirmation hearings revealed that he was nearly a millionaire, and his personal friends include influential lawyers and corporate executives.

Bell agrees that the director is low key. "I read all five of his FBI files and there's not a bad line in any of them. I've never read such files. He's just a straight arrow," the attorney general said.

Webster also is a "supper appointment," Bell said, because of his intelligence and background as a prosecutor and trial and appellate judge.

Those traits were evident during the director's visit to the Columbus FBI office. He adroitly fielded quesitons about pensions and retirement and terrorism and new limits on agents' use of private bank and phone rcords.

Among the listeners was Joe Yablonski, a soft-spoken, cigar-chomping veteran street agent whom Webster had just named "special agent in charge" (SAC) of the Cincinnati field office. Yablonski was on e of the bureau's first un lercover agents and is its first Jewish SAC.

The "senior resident agent" in Columbus, a 6-foot-8 former Baptist preacher named Tom Mitchell, was there, as were Tom Decker, an agent whose son is a quarterback at West Point, and Howard Linscott, one of 68 agents whom Webster decided not to discipline for their role in allegedly illegal 1970 breakings while searching for radical fugitives from the Weather Underground in New Yok City.

Webster is not shy about recitng the accomplishments of the men and women he leads, as his after-dinner speech that night showed. He expanded on his text enough to go on for 51 minutes.

Webster talked about his intent to carry on the shift in FBI priorities that started under Director Clarence Kelley's tenure in the mid-1970s. Kelley led the switch from chasing bank robbers and car thieves toward the pursuit of harber-to-catch white-collar criminals -- including politicians -- and organized-crime figures. Because Kelley was not articulate in public appearances, he has not receive the credit some FBI officials think he deserves.

Webster is an articulate, if undramatic, speaker. He spent part of his anniversary speech telling his audience that today's bureau is "accountable."

During the glory years of J. Edgar Hoover, who died in 1972, the FBI prided itself on being autonomous and beyond politics. But it also was unaccountable, and the misdeeds that Webster tries now to dismiss as "archeology" were an almost inevitable result.

Webster says the "residuals" from digging into the unsavory parts of FBI history "are still slowing us down."

For example, civil liberties groups trying to ensure against repetition of FBI spying on political dissidents want strict guidelines written into the proposed FBI charter now being considered in Congress.

Webster said he doesn't want the charter to be just a series of "thoushalt nots."

"I strongly resist calling it a 'curb-the-FBI' piece of legislation," he said. He expects it to be all-inclusive: "If we can't find a basis for acting in the charter, we can't do it."

Jerry Berman, an American Civil Liberties Union lobbyist, gives Webster high marks for discussing his group's concerns.

"We disagree on some basic issues, but at least there's a dialogue going on," Berman said.

The most difficult "residual" from the FBI past that Webster had to face in his first year was whether to discipline agents involved in allegedly illegal surveillance in pursuit of the weather Underground.

Former acting director L. Patrick Gray III and two former top aides were indicted for approving the break-ins, but their trial has been delayed because of complications over defense access to classified data.

In December, Webster announced he was taking no action against the street agents who actually carried out the breakins, "black-bag jobs," but was firing two supervisors, demoting another and suspending a fourth.

The suspended supervisor, J. Gerare Hogan, who was SAC in Milwaukee, wrote fellow agents in late December to discuss his case. He had written the director, he said, to express regret at having brought criticism on the bureau and a "problem of such magnitude" to Webster. "Mr. Webster has a reputation as a man of principle and integrity, and I don't think his decision was influenced by trying to placate our critics," Hogan wrote.

Webster still faces a nagging leftover from the breakins investigation: the possible coverup by high FBI officials of the extent of the surveillance. General Accounting Office probers and investigators for two congressional committees were given inaccurate data about the number of breakins, and Jim Adams, whom Webster quickly picked last spring as the bureau's No. 2 man, was the official who signed off on the material sent to Capitol Hill.

Adams told The Washington Post last year that he expects to be interviewed in the internal inquiry, but insisted he did nothing wrong.

Webster said in the interview that he has complete confidence in Adams -- a protege of old Hoover aides -- and no concerns about his honesty. "If I doubted his integrity I wouldn't want him around at all," the director said.

In other appointments, notably that of Neil Welch to head the bureau's largest field office, in New York City, Webster has reached beyond the Hoover-stamped elite at headquarters. Welch is known for his dislike for bureaucrats in Washington and was one of the first SACs to push investigations of public officials.

Webster also has kept his distance from the Hoover-era crowd by relying less than Kelly did on the "executive conference" of top headquarters officials. He recalls that some top officials complained about possible security problems and litter when he started opening the FBI courtyard for noontime concerts last summer.

But once he made that or any other decision, "I didn't find anyone out there in the woodwork trying to undercut me," he said.

During his firt year, Webster said, he set out to make every policy decision personally, unfilterd by his top executives, though this buried him under what he calls "buckets" of black folders marked "Immediate," "Expedite" and "Secret."

For example, he said he has moved to take ambiguous terms used to disguise techniques out of investigative reports, and to shift disciplinary sanctions away from an agent's conduct in private life to what he does professionally.

So far, Webster said, he hasn't run into nay political interference from Bell's Justice Department or the Carter White House.

The latter has been "singularly circumspect." Webster said. "It's been an ideal relationship, a cordial one, but one in which no favors were asked."

The new job leaves Webster with a lot less time than he'd like for his family, the farm with the four horses in Missouri, and reading about favorite subjects such as Great Plains Indian art.

His wife, Drusilla, (Dru), carried his tennis racket on the trip to Columbus "Everyone in the bureau knows I like tennis so I get in games when I can or trips," he said.

A favorite Washington pastime is escorting house guests, like the Korean War Navy shipmate in town over the weekend, to the Lincoln Memorial at night, the director said.

And yes, he told a questioner Saturday, he still cuts his own grass.

During confirmation hearings a year ago, Webster was asked if he might succumb to the perquisites of power as both Hoover and, to a much lesser extent, Kelley did in using bureau employes and supplies for personal favors. "I've cut my own grass for 25 years and I see no reason to stop," Webster said then.

When called Saturday, he chuckled at the question and said he had just returned home from the hardware store with a load of fertilizer and grass seed. His yard is too small to use the riding mower he brought from St. Louis, he said: "Know anybody who needs one?"