The Dutch artist and children’s author Dick Bruna, whose much-loved cartoon rabbit Miffy has sold more than 80m books since her creation in 1955, has died aged 89.

Bruna devised the character to entertain his infant son after they saw a rabbit in the dunes while on a seaside holiday. He went on to relate the bunny’s adventures in more than 100 books sold worldwide. Bruna wrote and illustrated more than 200 books over his career.

Miffy, known as Nijntje in Dutch, or “little rabbit”, enjoyed great popularity worldwide for both her book appearances and merchandise. But Miffy was not an overnight success; parents weren’t impressed with Bruna’s iconic simplicity: “They said, ‘Oh, that’s too simple. The colours are too bright and I don’t like blue and green together,’” he told the Guardian in 2006. “But I thought it was nice to make everything as simple as possible to give children lots of room for their own imagination.”

Bruna, who also worked as a graphic designer, spent years finding the specific red, blue, green and yellow that would become known as the Bruna colours. He would later expand his palette for Miffy’s friends Snuffy Dog, Boris Bear and Poppy Pig, but again agonised over the right shade of grey, brown or pink. Despite all of the books, he said that he found drawing Miffy’s eyes and famous ‘x’ shaped mouth hard: “That’s all you have. With two dots and a little cross I have to make her happy, or just a little bit happy, a little bit cross or a little bit sad – and I do it over and over again. There is a moment when I think, ‘Yes, now she is really sad. I must keep her like that.’”

Dick Bruna posing at the opening of his exhibition Miffy Creations in The Hague in 2005. Photograph: Inge van Mill/AFP/Getty Images

Born in 1927 into a family of publishers, Bruna discovered Matisse and other modernists on a trip to Paris. Afterwards, he would refer to these artists as his teachers. He began his career as an illustrator of book jackets, including Ian Fleming’s James Bond series and Georges Simenon’s Inspector Maigret thrillers.

But it was Miffy that would make him a celebrity. Fans from all over the world, particularly from Asia, would make trips to Utrecht to visit the artist’s museum, the Miffy Museum, as well as his own house, where he lived for more than 40 years. One Japanese couple even took their honeymoon in the city especially, delivering Bruna a Miffy-shaped cake while they were there.

Despite having huge financial success with Miffy’s merchandise, Bruna worked seven days a week and rose at five every morning. He would start each day by drawing a little picture for his wife Irene, of something related to her day, such as a visit to the doctor or a game of bridge. He told the Guardian in 2006 that life had remained the same for him: “I just see it as a very ordinary job. There is nothing else I can do, apart from make little drawings and stories.”

Bruna produced his last Miffy book in 2011 and retired in 2014. His death was announced in a statement by his publisher. He died in his sleep on Friday.