MUSIC : Leading Man : Keith Lockhart, the Pops’ new man on the podium, has taken Boston by storm. And not just because he makes beautiful music.

It’s one of the longest-standing traditions of an institution steeped in them: Rain shall not fall when the Boston Pops plays its summertime outdoor concerts. For as long as anyone could remember, it just didn’t happen. So what was that drizzly stuff coming down early this summer, outside Hatch Shell, the Pops’ venue along the Charles River?

Four thousand hard-core fans were dismayed, not to mention soaking wet. Unable to reverse the latter condition, the Pops’ newly ensconced conductor, Keith Lockhart, was nonetheless eager to ease the former.

He bounced to the podium, and graciously explained that string players prefer not to drown $200,000 wooden instruments: The concert would have to be canceled. As a small consolation prize, however, he marched the wind section into the shell to pipe out a Pops perennial, “Stars and Stripes Forever.” Lockhart used his umbrella as a baton.

If one tradition died, another one didn’t: The crowd left humming.

In his inaugural season with the Boston Pops, Lockhart has been working that particular trick over and over: ushering in change with enviable aplomb. Rain or shine, his has been a triumphant takeover in Boston.

For him, it’s a clear case of wish fulfillment. “For a lot of us who grew up in the 1960s and ‘70s,” Lockhart said, “the Boston Pops Orchestra was among the first we ever heard. That certainly was the case with me. It was always my dream--it’s every conductor’s dream--to work with that ensemble.”

*

So far, Lockhart’s enthusiasm is entirely mutual. After the the season opener, in the first of what would be a string of complimentary notices, the Boston Globe called him “a real conductor” who “pulled it all together with limited rehearsal time under high pressure.” And just two weeks ago, the patrons offered up their own enthusiastic review: The Pops received a $5-million donation earmarked to endow Lockhart’s conductorship.

The ease of Lockhart’s ascension belies the challenge. In Boston, the Pops rates icon status. It by no means plays second fiddle to its parent group, the esteemed Boston Symphony Orchestra (in fact, the Pops Orchestra is the Boston Symphony, minus the first-chair players; the Pops Esplanade Orchestra, responsible for most of the summer concerts, is made up of free-lance musicians). Born in 1885, in an attempt to emulate summer concerts in the gardens of Vienna, the Pops this year packed close to 400,000 fans into its July 4th concert, a near-sa cred Beantown tradition. Installing a new conductor thus takes on a devotional dimension.

In truth, Lockhart’s arrival has been greeted as the Third Coming here. He follows in the enormous musical footsteps of Arthur Fiedler, who ruled the Pops from 1930 to 1979, and John Williams, who stepped down last year. Newspaper headlines trumpeted Lockhart’s appointment with the kind of excitement normally reserved for declarations of war or peace--or in this part of the country, anything having to do with the Kennedy family. His professional accomplishments were touted--no, shouted: three years as associate conductor of the Cincinnati Symphony Orchestra, a decade of teaching at Carnegie-Mellon University in Pittsburgh and plenty of free-lance credits. His stint as the backup pianist for an Elvis impersonator usually is not mentioned in these accounts, nor does his official resume take note of his work as a clarinetist with the Ringling Bros. and Barnum & Bailey Circus Band.

Not that Lockhart’s musicianship is in question. His conducting style is often likened to that of a young Leonard Bernstein: fluid and, in the words of one critic, “on the verge of levitating.”

He has conducted in Chicago, Louisville, Akron, Toronto, Greenville, S.C., and Naples, Fla. As a fellow with what he called the “very sadly defunct” Los Angeles Philharmonic Institute in 1989, he first played the Hollywood Bowl--where Lockhart and the Pops Esplanade Orchestra will appear tonight. A Times review from those days noted Lockhart’s “impeccable and well-defined podium manners” and “clear sense of motion.” Lockhart, for his part, recalled the Bowl as “a sociological experience, not just a concert venue,” memorable for “the ambient noise, the sound of a wine bottle that gets kicked down the steps and rolls slowly for 40 seconds or so. Or the Hollywood Hills homeowner who suddenly kicks in with his buzz saw.” The result, Lockhart said in fond retrospect, was “Beethoven’s Ninth meets ‘Texas Chainsaw Massacre.’ ”

But the resume of this 35-year-old native of Poughkeepsie, N.Y., has generated only slightly more enthusiasm in staid old Boston than--no kidding--his sex appeal. The big question as his first concert loomed was not what piece he would conduct, but whom did he resemble most, Tom Cruise or Hugh Grant?

“Aaaaaaggghhh,” Lockhart groaned. “The other day someone said they saw me on the street--in a parked car.”

Those who see him on the street--or anywhere else--are apt to pounce on Lockhart with autograph requests or more explicit entreaties. And he confides that several arts aficionados have proposed marriage--a possibility, actually, since Lockhart has for many years been divorced from the college sweetheart to whom he was briefly married.

I n seeking a new conductor, the Pops had made no secret that it wanted someone telegenic. Early this year, PBS withdrew funding for its long-running series, “An Evening at the Pops.” Along with its nationwide tour, the series is a prime Pops vehicle for ensuring its status as “America’s orchestra.” Lockhart’s appointment, however, moved the Gillette Corp. and Fidelity Investments to step in as corporate white knights, guaranteeing three Pops PBS concerts this season.

Showmanship was another area where Lockhart ranked high in the two-year search for a new Pops leader. In fact, that was among Lockhart’s hallmarks in Cincinnati, where he was known to rise out of a coffin for a Halloween concert, descend from the ceiling in a spaceship for a performance of “Also Sprach Zarathustra” from “2001: A Space Odyssey,” and parade into the concert hall on the back of an elephant to lead the triumphal march from “Aida.”

Lockhart is quick to defend such antics. “They were for kids’ concerts,” he said, and his high jinks were hooks, on the theory that whatever it takes to get young people interested in music is probably worth the effort.

“It’s important, I think, in these days. We live in such a visual age,” Lockhart said. “We have a big disadvantage in a primarily aural medium. To ignore that is stupid.”

Still, some of the Pops musicians were less than thrilled when Lockhart invited noir magicians Penn & Teller to perform. The duo, it was suggested, impugned the dignity of the institution.

“ ‘The dignity of the institution,’ a phrase I really hate,” Lockhart said. “I think institutions should not have dignity. I think people should have dignity.” Besides, he shrugged, and his smile turned impish, “Hey, I’m a ham.”

Lockhart’s love of applause showed up early. Like most 5-year-old boys in Wappingers Falls, N.Y., Lockhart dreamed of being a baseball player. Piano lessons when he was 7 took him in a different direction, as did his slight physical stature. “I barely broke 5 feet when I started high school,” he said.

Since both his parents worked in the computer industry, a performer in the family was an anomaly. In high school, young Keith happily drifted off with what he confessed was the geeky arts-and-music crowd. At Furman University in South Carolina he switched from pre-law to a double major in music and German. Mahler remains among his all-time favorite composers. In his car, though, he is just as likely to listen to the Who.

Such protean tastes are a precursor of the direction in which Lockhart will take the orchestra.

Mindful that Bostonians “adore this institution,” Lockhart recognizes that its image has grown musty. “What you hear people my age, 35 to 45, saying is, ‘The Boston Pops is a great thing. I’d like to send my parents there for their anniversary,’ ” Lockhart said.

Convinced that the Pops’ musical mix “is sellable to people my age and even 10 years younger,” Lockhart proposes to root his seasons in “the stuff that appeals to your older, traditional group in a way that makes them realize that you are serious about their music, but also leaves a little leeway to push to the edges.” Lockhart would like to bring in artists like “Mariah Carey, a wonderful, trained vocalist with a legitimate classical background,” or Billy Joel and Paul Simon, “whose music is often orchestral in concept.”

Such moves, he reasons, would dispel a prevailing perception about the Pops: “Unlike other things that people do for entertainment, nobody’s allowed to have fun at a Pops concert--which is such a crock,” Lockhart said.

He has equally little patience for “effete snobs” who disdain the Pops’ light music as lite music. “That attitude has always burned me up,” Lockhart said. “I think, what a horribly unconstructive way of looking at music. To think that serious music could be performed in only one way, could be only one thing, that’s obscene.

“You ask what my mark will be?” he said. “Maybe I can put a big huge dent in that kind of thinking.”

H is frankness helped Lockhart glide across the final hurdle in his courtship with the Pops--an interview with BSO music director Seiji Ozawa. Lockhart was apprehensive, but Ozawa quickly put him at ease, and in announcing Lockhart’s appointment, praised him as “a musical spirit without boundaries.”

As a certified free spirit, Lockhart is certain that even in Boston, his irreverence will become endearing. “The reaction has been that I should try to become fresh and exciting--not fresh in the other way,” he said. In any case, he stressed, “I have great respect for an institution that has lasted 110 years.”

Even so, Lockhart clutched momentarily when the full significance of his new job set in. “It struck me that all my other life decisions were probably easier, because they didn’t have that permanence associated with them,” he said. “This is really irrevocable. No matter what happens, I will always be the conductor of the Boston Pops. No matter how great that is, it’s kind of scary.”

For an instant Lockhart gazed off, as if contemplating the prospect of playing a role in Pops history. Then his dazzling grin flashed back on. It seems that Keith Lockhart doesn’t stay scared for long.*