Author-illustrator Oliver Jeffers, a Belfast native who has lived in Brooklyn since 2007, is enjoying his greatest U.S. success to date with Stuck, his eighth and most recent picture book. The book sold out its original 20,000-copy print run and to date has 50,000 copies in print. But Jeffers had already made a much bigger name for himself in the U.K., beginning with his 2004 debut, How to Catch a Star. That plucked-from-the-slush-pile submission went on to win a Merit Award at the following year’s Bisto Book of the Year Awards in Ireland.

Since then, Jeffers has racked up multiple nominations and honors overseas. Lost and Found, published in 2005, nabbed the Nestlé Children’s Book Prize Gold Award and was named the Blue Peter Book of the Year. In 2006, The Incredible Book-Eating Boy made Richard and Judy’s Christmas shortlist (tantamount to an Oprah recommendation) and was named Irish Picture Book of the Year. The Great Paper Caper was shortlisted for the 2008 Roald Dahl Award, and The Heart and the Bottle (2010) was shortlisted for the Kate Greenaway Medal, the U.K.’s answer to the Caldecott.

His latest book is The New Sweater. Like other Jeffers titles, it is being released simultaneously with HarperCollins in the U.K. and with Penguin/Philomel in the U.S., thanks to an unusual publishing backstory. “Oliver began by blindly submitting his miniature dummy for How to Catch a Star to publishing houses on both sides of the Atlantic,” says Michael Green, president and publisher of Philomel. “Not knowing the business or the editors, he submitted to presidents of young reader divisions in America and to their equivalents in the U.K.” When Star landed at Penguin, says, it was on its way to Grosset and Dunlap when a sharp-eyed junior editor at Philomel nabbed it. Green contacted Jeffers that very day.

The illustrator already had a New York trip planned, and made Philomel his first stop. By the end of their meeting, Green says, “he told me that Philomel would be his U.S. publisher. I was thrilled.” At the same time, though, HarperCollins U.K. had also shown strong interest. Green says he encouraged Jeffers to work with them – “not that he needed my encouragement” – and the author signed a multi-book contract with the British publisher for world rights. But, says Green, “he was true to his word and told Harper that he wanted Philomel to publish his work in America.” Soon after, Jeffers’s U.K. publisher visited Penguin U.S., and thus began an unusual partnership between two rival houses.

For every title, Philomel acquires rights from HarperCollins U.K. for simultaneous publication. Says Helen Mackenzie Smith, editorial director of HarperCollins Children’s Books in the U.K. and Jeffers’s editor there, “We’re the originating publisher, so Oliver works on the idea with us, and then we work on it with Michael [Green].” Green adds, “In truth, Oliver doesn’t require much editing. It’s more about conversation and making sure his intent is coming through in the sparest of manners. Oliver always has a strong sense of what style his art will take and how the package will be designed.” Each company develops its own marketing and publicity plans, though, as Mackenzie Smith says, “It’s been a useful thing to share marketing assets. It’s been really fantastic that it’s been such a long relationship, and it’s enabled everyone to work strategically and collaboratively.”

There are, of course, some differences between U.S. and British versions of Jeffers’s books: The New Sweater, for example, has a slightly larger trim sizein the U.K. –“We don’t really have the 8x8 format,” Mackenzie Smith explains – and in deference to local vocabulary, is called The New Jumper; Jeffers did the lettering for both.

Sweater (or Jumper) launches a series called the Hueys, something of a departure for the author. “The Hueys happened by accident,” he says. “It started as drawings in a sketchbook, a pitch for something that never happened. And I thought, there’s something here. It came together quite quickly. It’s not a narrative in the same sense as my previous books. It’s smaller, simpler.” The Hueys are egg-shaped characters who all look and think alike and, Jeffers says, “are fascinated by the pointless.” In Sweater, one Huey knits a pullover that makes him stand out from the rest, which causes rather a stir among his conformity-minded fellows. “The first book in the Hueys was conceived as an introduction to the characters,” the artist says. “Some of the next books will be more like conversations between the characters, like overheard playground conversations between children.” Eventually, he plans to use the characters in concept books, to relate ideas like opposites and numbers. The second Hueys book is due out in May 2013, but before that release, he’ll return to narrative form with This Moose Belongs to Me, due out this November.

Jeffers’s work as author-illustrator of his own books keeps him quite busy, but he also finds time to collaborate with other writers and artists. He met Irish novelist John Boyne (The Boy in the Striped Pajamas) a few years ago, when each was nominated for the British Children’s Book Award. Both were rooting for Terry Pratchett that year, and Jeffers says neither he nor Boyne cared much for the book that did win, but they were fans of each other’s work. “We met up when I was in Dublin for dinner, and began talking about working together,” says Jeffers, who went on to do the art for Boyne’s Noah Barleywater Runs Away and the forthcoming The Terrible Thing That Happened to Barnaby Brocket.

Other collaborations sprouted a bit closer to home. Jeffers used to share a studio in Brooklyn with jewelry designer Aaron Ruff and animator/collagist Mac Premo (he now has a space next door to them). “We have a shared sense of aesthetics and would ask each other’s opinions, so it was inevitable that we’d cross-pollinate,” Jeffers says. “One day, the three of us were talking about things that exist in the world, and things that don’t. We thought, ‘This is a good idea. Let’s make this.’ ” “This” turned into You and Me the Royal We, an eclectic line of wares such as a leather belt with a poplar-bark buckle, and temporary Tattoos of Truth, which riff on classic skin art (the text on what looks like a typical anchor, for example, reads “I’ve Never Been on a Boat”). Jeffers also worked with Ruff on a collection for his Digby & Iona line of jewelry, based on characters like the boy from How to Catch a Star and subsequent books, and the penguin who got his start in Lost and Found.

Jeffers characters have also found life in other media, and several of his books have been adapted for the stage. “I don’t get involved with that because I don’t know much about theater,” he says. “I see the productions when I can. It’s been fascinating how imaginative these companies are, what they do with so few props.” The author was more involved in the animated short film version of Lost and Found, which first aired in 2008 on the U.K.’s Channel 4 and went on to win multiple awards, including the BAFTA (Britain’s equivalent of an Emmy) for children’s animation; due to rights issues, it’s yet to air in the U.S.

Jeffers is also making forays into electronic publishing. His first title to be released for the iPad, The Heart and the Bottle, was named app of the week in the U.K. by Apple’s App Store team. The author, too, was pleased with the translation from paper to e-book. “The interactions were relevant,” he says. “Whenever the girl is curious, the interaction involves adding things into the story. When she’s sad, you withdraw things, making her world empty. It’s not just adding a whistle here. The interactions further the story.”

The New Sweater is launching with an app that lets users develop a personalized Huey by answering a series of preference questions. But whether a user’s creation plays accordion or guitar, or wears cat’s-eye spectacles or Roy Orbison-style shades, one signature trait remains – like all Jeffers characters, the Hueys have stick legs that end right at the ground, lacking appendages at the end. “Kids ask, can you draw feet?” Jeffers says. “And I can actually draw feet. Well, shoes.”