So what persuaded him to write a novel for children about superheroes and sibling rivalry told from the point of view of a comic book-obsessed brother who misses out on being granted superpowers because he goes for a wee at the wrong moment?
"I was really worried about becoming a dad. I thought the arrival of a child would compromise my creativity," he says. "But when Luke was born, actually I felt this need and urge to write something for him."
The pivotal moment came in New York, where Mr Solomons had accompanied his wife, the novelist Natasha Solomons, on a book tour.
"Luke was with us and he was in a Superman outfit standing by the hotel window, looking out over the metropolis. There was something in that image."
He adds: "Also I wondered if there was a way of telling the traditional superhero story differently. What if it is not about the chosen one, but the one standing next to him? Those were the two strands."
Mr Solomons cites Douglas Adams, author of The Hitchhiker's Guide to the Galaxy as the biggest literary influence on the book. Characters include the Hitchhiker-esque "Zorbon the Decider, an inter-dimensional traveller and representative of the High Council of Frodax Wonthreen Rrr'n'fargh".
"Humour infuses everything that I write," Mr Solomons says. "It's not always appropriate. I have got a terrible terrible weakness for puns, and in adult fiction it is frowned upon, but children love it, so this feels like the right avenue for that kind of writing."
He adds: "It came as a surprise to me that I had written a children's book. I was partly thinking about my son in 10 years' time but I was writing it for me. To get through the marathon of writing a novel you have to get something out of it. I think it turns out I had the sense of humour of an 11-year-old boy. It's quite self-indulgent."
He credits that sense of humour to his Jewish roots, "It's ingrained", he says.
Although there are no overt Jewish references in the book the author describes the hero - called Luke, funnily enough - as, "a bit of a nebbish - slightly down-trodden, he feels hard-done-by. There's a lot of me in him."
Mr Solomons grew up in Glasgow where he had a traditional Jewish upbringing and attended Giffnock Synagogue.
"One thing I miss hugely is not being able to go round to Mum's for Friday night dinner." When he visits he makes sure it includes a Friday night.
Those visits are long-haul affairs. The Solomons - David, Natasha, Luke and seven-month-old daughter Lara - live around 450 miles away in rural Dorset. "Yes, we're the only Jews in the village," he says.
The couple have installed a studio in their garden where they write, and occasionally collaborate. Pre-parenthood they would go for long walks in the countryside and discuss plots.
They are currently working on a joint screenplay about Jewish, Brazilian writer Clarice Lispector. Mr Solomons admits: "There is this low-level background bickering, but I think we complement each other."
Mrs Solomons, who is perhaps best known for her books Mr Rosenblum's List and The Song Collector, "brings an intellectual vigour and poetic quality to writing that I have not got," he says.
The naming of their two children "sums up my wife and I", Mr Solomons suggests. He named Luke, who's now three-and-a-half, after Star Wars hero Luke Skywalker, while Mrs Solomons named Lara for the heroine of Doctor Zhivago.
With the Waterstones trophy sitting proudly in their home, life is pretty good for the newly-emerged children's fiction superhero.
"This is the biggest success I have ever had. I'm very happy to see what I can make of it.
"I have been writing full-time for over 20 years. There have been some fallow times, a lot of rejection. It feels pretty good at the moment so I'm going to enjoy it."
The sequel, My Gym Teacher is an Alien Overlord, is already on its way to the printers and Mr Solomons has begun work on book three.
And what did he listen to while writing a book about space and aliens? The score to the latest Star Trek film, of course.
My Brother is a Superhero has also been shortlisted for the Independent Bookshop Week book awards in the children's category. Winners will be announced in June.
Who is your favourite Jewish children's author? Take a look at our top 10 and see if you agree.
