It was not quite as monumental a deal as when multinational conglomerate Bertelsmann swallowed up publishing giant Random House for more than $1 billion. But after 45 years under the radar, it was time for small, prestigious Walker & Co. to step up to the plate and swing for the fences.

Last month, Bloomsbury, the British publishing company behind the Harry Potter books, paid about $7 million to acquire Walker, a family owned business started by Samuel Walker Jr. in 1959.

“Walker was like a high-quality, small-market independent team,” says Walker’s publisher, George Gibson. “I don’t know if we were a Major League franchise, and we needed to be a Major League franchise. We were good enough to be a Major League franchise, but we needed the resources. I really think that it could not be a better alliance than what we have now with Bloomsbury.”

Although Mr. Gibson and his staff will now have to go through a more bottom line-oriented chain of command when buying books and developing marketing programs, they will also have greater access to the marketplace. Bloomsbury’s titles are sold and distributed by St. Martin’s Press, part of von Holtzbrinck, which also owns Henry Holt, Macmillan, and Farrar, Straus & Giroux, among other houses.

The deal came as a shock to many in the industry. Just four years ago, Mr. Gibson told the trade magazine Library Journal that the Walker family “wanted to remain independent, fiercely so.”

But things change.

“It’s hard to say that a small, independent, family-owned trade publisher is a highly liquid asset,” Mr. Gibson explains now. “It’s not. It can’t be.”

Mr. Gibson himself is one of Walker’s greatest assets. He arrived at the firm in 1993 after spending nearly 20 years at Little, Brown and David R. Godine in Boston and Addison-Wesley in Reading, Mass., mostly in the sales and marketing departments. The Harvard graduate’s first job after college was a short stint at the Old Corner Bookstore in Beantown, then the “oldest continuously running bookstore in the country,” he notes.

“Independence is a wonderful thing,” says Mr. Gibson. “You can do anything you want to do – obviously, you have to make money at it, but it’s a wonderful thing. But we realized, over the last couple of years, that being a stand-alone independent publisher, doing everything ourselves … it was getting harder and harder to compete.”

Dressed casually in a sweater and sneakers, Mr. Gibson is the only person in the Walker offices near Union Square on a dark Sunday night. The tiny company is eerily quiet. Mr. Gibson prefers to do his editing in silence so he can “get inside the author’s head.”

“You can work 24/7 and never be caught up, never take advantage of all the opportunities that are out there, never satisfy all the things you want to do,” he says. “We’re all somewhat crazy working in publishing, because none of us will ever make near the money someone can make working far fewer hours in some other industry. But we do it because we love it. It’s in our blood.”

Mr. Gibson, a youthful 54, was born and raised in Manhattan. He has been married for eight years to Linda Johns, who now runs WalkerBooks.com. Except for one year devoted to studying Italian, Mr. Gibson has spent his entire 32-year career in the book field. Unlike many publishers who spend their weekends at second homes in the country, Mr. Gibson spends what free time he has going to dinner parties and the theater in New York City with Ms. Johns. They do love traveling to Europe when they can, however. Mr. Gibson has also recently resolved to renew his tennis game.

“I’ve always considered George a gentleman of the old school of publishing – which I mean as the most sincere form of compliment,” says an executive editor and vice president at Ballantine, Joe Blades. Mr. Blades survived Random House’s surprise acquisition by German behemoth Bertelsmann in 1998. “George is dedicated to authors and passionate about their books. And he’s to be commended, particularly in these rocky times in the industry, for finding a way to be both pragmatic and forward-thinking.”

It’s that passion and forward-thinking that helped propel Walker onto the New York Times best-seller list in 1995 with Dava Sobel’s publishing sensation, “Longitude,” the fascinating story of John Harrison and the invention of the marine chronometer in the 18th century. Mr. Gibson first read an article by Ms. Sobel on the subject in Harvard magazine and immediately contacted her to turn it into a book. Later this year Walker will release a 10th-anniversary edition with a foreword by Neil Armstrong as well as a special color section.

“‘Longitude’ was all about passion,” Mr. Gibson says.

Current Walker books Mr. Gibson is passionate about include M.G. Lord’s “Astro Turf,” a first-person account of a young woman’s search for her father’s love amid the world of rocket science, and “The Bonus Army” by Paul Dickson and Thomas B. Allen, which Mr. Gibson believes “will be one of the most important books on American history that will be published this year.” The illustrated hardcover examines the 1932 march on Washington for veterans’ rights.

Mr. Gibson also speaks proudly of Walker’s children’s division. He’s especially excited about two upcoming spring titles: Kathleen Krull’s picture book biography of Harry Houdini, illustrated by Harlem native Eric Velasquez, as well as “Blood Red Horse,” a first novel by K.M. Grant.

“There’s an incredibly positive trend – kids are spending their own money on books,” Mr. Gibson explains, pointing out how successes such as the Harry Potter series have helped encourage children to read in a world cluttered with so much “noise.”

Mr. Gibson is also passionate about baseball. Despite his New York roots, he is an Atlanta Braves fan who admits to hating both the Yankees and the Mets while also rooting for the Red Sox. A rotisserie league devotee, he is “mortified” that his wife has become a Bombers backer.

“When I first became conscious of baseball, it was 1957; I was 7 years old,” he remembers with a gleam in his eye. “That year the Braves and the Yankees – the Milwaukee Braves – played in the World Series. And the Braves came back from three to one down to beat the Yankees, a total upset.

“They were the tiny small-market team from Milwaukee; no one had ever heard of half their players – Warren Spahn, Lew Burdette, Hank Aaron, Billy Bruton, Eddie Mathews, Joe Adcock. Burdette won three games in that series and beat the Yankees 5-0 in the seventh game. And I became a Braves fan for life.”

Just like Mr. Gibson’s affection for small-market underdog Milwaukee, it’s hard not to root for onetime independent Walker as it makes its way into the big leagues.