“Somebody once said, ‘Don’t go visiting the graves of the demons you’ve buried,’” Paul Jennings recalls with a small laugh. It sounds like the start of one of his short stories.

Normally when the beloved children’s author puts pen to paper, the result is something surreal or fantastical. This is the creator of Round the Twist, the author of Unreal, known for writing about things like remote controls that can fast forward or rewind time; bugs that can turn your skin transparent; a long-dead fox that comes slowly back to life after being fed lemons.

For his latest work, however, he has made the move from fiction to reality, with a bittersweet memoir that offers an unexpected new context to his stories, navigated with both humour and sadness.

“It was painful,” he says, of writing his thoughtful and unusual memoir, Untwisted – The Story of my Life. “Some of the things, members of my own family didn’t know about.” But now, at 77, the memoir “was just something I felt ready to do – and I’ve enjoyed it but also it’s been quite confronting”.

Perhaps better than anyone else, Jennings knows the power and impact words can have on children – first, from his own childhood, then through his years as a teacher, and finally as a writer.

Untwisted opens at an ending: it’s 1983, Jennings’ marriage has broken down, and he is now a single father of four living in a half-finished house, looking down the barrel of losing his job. Moving back and forth across his life, Jennings takes readers through highs, lows and unexpected turns, and doesn’t shy away from the weird or the personal – such as the moment when, so stressed by the precariousness of his finances and his crumbling marriage, he hid in a wardrobe. He also explores the intrusive, violent images he started getting at the age of 11, which made him question his own sanity.

Throughout the book Jennings identifies the line between truth and fiction, and quietly shows readers the origins of his ideas. In writing something like this, “You can see all the connections in your life and the places you’ve made mistakes,” he says. “I feel that if you’re prepared to bare your soul a little bit, which some writers do, it is useful to other people.”

He recounts an important meeting with a publisher – his big break – where he drove hours in a hot car, and then, when he went to change into his formal clothes, realised he had forgotten to pack his trousers. Later, in the TV series Round the Twist that he adapted from his short stories, one of his characters finds himself saying “without my pants” at the end of every sentence. It’s a mirror between his life and his work that’s too strange to be a coincidence.

If you look back at his work, it turns out Jennings has actually been baring his soul through his fiction since the very beginning; the memoir is just lifting the final barrier. Jennings talks about one recurring theme in his writing being “the sorrowful woman”. He laughs. “The little boy’s always trying to make his mother happy – I did that quite a few times without realising that was what I was doing.”

In Untwisted we see, perhaps, where this preoccupation came from. Early on he lays out a memory from his childhood – told, he explains in the book, in third person because “maybe I’m protecting myself from feelings that are still raw”. In it, his mother is pulling him along on his Christmas present, a sled, and even at such a young age he feels guilty, like a burden. He can feel her sadness but at this stage doesn’t know the reason why. Later, he learns, it’s because of the then-recent suicide of her brother. “For the rest of his life he will feel the need to make her happy,” Jennings writes.

In his memoir he tracks significant words through his own life. At 12 he unsuccessfully submitted a story to Australian Women’s Weekly – the rejection stung, and he didn’t write again until he was almost 40. He also lists, verbatim, lines his father said to him as a child, seared into his memory:

“You will never be fit for anything but the workshop.”

“Shut up. It’s all your fault.”

“That was to teach you about electricity.”

His father’s presence, which swings from indifference to cruelty, haunts the book. Jennings explains that writing it all out – and being able to look back over separate incidents – allowed him to gain new understanding. “I was surprised at the degree it brought things from the past to life with more clarity than I’d ever had before,” he says. Even though it was painful, he is glad he wrote it. “The book was a form of therapy, even though that wasn’t the main point.”

His fiction isn’t necessarily a way of him rewriting his own past to be more how he would have liked it, but a way of offering young readers a lifeline. “The children in my stories nearly always come out on top by some miraculous happening or by some craftiness, and I do think it makes them feel empowered … and maybe even a little bit of hope.”

With Untwisted, he says, “I wanted it to be a different sort of memoir.” He confesses early on to readers that he is in new territory – so he breaks the fourth wall regularly to check in and explain his choices. In between the stories and the self-examination it’s also, strangely, a really good guide to writing for children, offering advice to the next generation of children’s writers to help them understand why the right words, the right story and the right amount of empathy can be so important.

• Untwisted: The Story of My Life by Paul Jennings is out now through Allen and Unwin