Eric Hill, who has died aged 86, was one of those unusual and fortunate people whose first book was not only an immediate success but also became a staple of children's bookshelves for decades. Where's Spot?, a simple lift-the-flap picture book with a lovable puppy at the heart of every picture, was published in 1980. Within weeks, it was a bestseller, taken to the hearts of pre-schoolers and their parents across Britain.

That immediate success was no flash in the pan: the many sequels that followed included Spot Goes to School (1984) and Spot Goes on Holiday (1985); Spot's adventures were translated into 60 languages; and sales figures topped 60m copies worldwide. And then there were award-winning adaptations for television and DVD, and all kinds of merchandising. More than 30 years later, Spot is a ubiquitous character who can be found on everything from stationery sets to bed linen, and is one of the most recognisable brands for young children.

As with many other popular children's books, the ideas for Spot came from close to home. The little puppy first appeared in the bedtime stories that Eric, a freelance graphic designer, told his son, Christopher, born in 1976. When it came to writing the story down, Eric drew on an advertising flier he had created, which had a flap that lifted up to reveal something amusing. Finding that Christopher was entertained by the device, Eric used it as a way of telling the story about Spot who, within a very domestic interior, simply sets off to search for his missing ball. At each wrong location, a surprise is revealed.

Just as flaps were helping to tell the story in advertising, so they had become part of picture books, too. Technology had enabled books with moving parts – flaps, tabs and pop-ups – to take hold; typically, these were busy books with a high entertainment value designed to appeal to as many readers as possible by moving away from bookishness and towards games and toys.

Eric took another tack; he created a book that was as simple as it could possibly be. He was determined to make every line count – very much in the way Dick Bruna had done when creating his Miffy titles – and to give every page the same look and structure. The one flap and one surprise on every spread drew young readers in and cumulatively gave them a story.

At the time, the idea was bold and original. Judith Elliot, then editorial director at Heinemann, remembers well the shabby little dummy that she was shown because it was completely unlike anything she had seen before. The simplicity of Where's Spot?, combined with the quality of Eric's drawing and design, set it apart. "Eric had a very strong design philosophy which was all about paring down and paring down," said Elliot. "It was that which fuelled his work on Spot. We were instantly thrilled by it."

Eric had a sharp eye for the market and knew exactly how he wanted the books to look. He chose the distinctive typeface – Century Schoolbook Infant – and, initially, insisted that images of Spot should be created only against white paper. His vision was kept intact in the original titles; but as the merchandising snowballed, variations in the typeface appeared and Spot began to be seen against all kinds of backgrounds.

The attention to detail was part of Eric's belief that Spot books should be produced to the highest possible specification, to make each one a work of art as well as an engaging toy. But the austere approach to design did not detract from his underlying view that Spot should have a playful element at its core. Speaking after the books had established themselves, Eric said: "I believe it's the sense of fun that makes the books so popular."

Amiable and warm-hearted, Eric put much of himself into the books, saying in a later interview: "When he shows excitement on Christmas Day and cries 'Yippee', that's me in there. I love the character, he's my buddy and I'm at ease with him. Subconsciously, I see things from the dog's point of view, so Spot is within me."

It really mattered to Eric that children enjoyed the books and he was moved when he was once presented with a family's much-loved and somewhat battered copy of Where's Spot? to sign, as it reflected how much it had been used and enjoyed. Over the years, he identified more and more with Spot, to the extent that he would say: "Spot wouldn't like …"

Eric was born in London, where he also went to school. His first job, at the age of 16, was as a messenger in an art studio, where he was encouraged to draw comics in his spare time. Following service in the RAF after the second world war, Eric returned to the studio and developed his cartoons, which led to a weekly strip for Illustrated and sketches for the monthly magazine Lilliput. He moved into advertising and later worked with the graphic designer FHK Henrion at the advertising agency Erwin Wasey. He then became European creative director for an agency which folded just four weeks later, prompting him to go freelance.

With the global success of Spot, Eric gave up his freelance work and moved to the US. Having long enjoyed staying on dude ranches, he and his second wife, Gillian, settled first in Tucson, Arizona, where Eric took to wearing cowboy boots, a Stetson and Navajo jewellery, and later in California. From then on, they divided their time between California and France.

Eric was proud to be selected as one of a handful of "literary ambassadors" at the Children's Party at the Palace in June 2006, one of the events held to celebrate the Queen's 80th birthday. In 2008 he was appointed OBE for services to children's literature.

He is survived by Gillian, Christopher and a daughter, Jane, from his first marriage, to Barbara, which ended in divorce.

• Eric Hill, writer and illustrator, born 7 September 1927; died 6 June 2014