Her Shop Girls and Victory Girls books, inspired by Wolverhampton's famous department store, Beatties, have won fans all over the globe.
But Jo says the time has come to draw the series to a close - although she hasn't completely ruled out catching up with best friends Lily, Beryl and Gladys again in the future.
"I know them like my own family. I could happily write about these characters for the rest of my life and the rest of theirs, but for now, this seems to be a natural ending and a good place to pause," she tells Weekend.
The former scriptwriter for radio drama The Archers was first inspired to start writing the series after visiting an exhibition that showcased the history of Beatties and provided a fascinating insight into the department store's heyday.
Her debut novel, A Store At War, told the story of a young girl called Lily who gets a job as a junior in department store Marlow’s in 1941.
The following books in the series have followed Lily, her friends Beryl and Gladys and colleagues at Marlow’s as they deal with the challenges of wartime as well as their own relationships and family issues.
The latest chapter, Wedding Bells for the Victory Girls, is set once again in the fictional town of Hinton, which Jo says is based around Wolverhampton, Dudley and Tipton, in June 1945.
"The war is over in Europe but still going on in the far east. The book starts with Lily and her boyfriend Jim getting married. I want all my character to have happy endings but in life a little rain always falls so there's always been something happening that has stopped them from getting married before now. Gladys has been married for some time and now has toddler twins.
"Her husband is back from serving in the Navy but it's not the happy homecoming Gladys hoped for. Bill hasn't got a job to come to and he struggles to find work. Gladys has always been the mousy one but she's determined to make a life for herself and Bill and for her family. Beryl's bridal business is under threat but help comes from a place she would never have expected.
"There were characters I needed to bring back because there stories were unresolved. One of these is Robert Marlow, the son of Cedric Marlow, the owner of Marlow's. He's back but not in a good way, although it turns out to be a good thing for Beryl.
"The beating heart of Hinton has always been Lily's mum, Dora. She had a warm friendship with a Canadian corporal but he had returned to Canada. It seems to be a loose end that needed tying up. All I'll say is that Dora gets her happy ending.
"All of the favourite characters are there including Lily's sophisticated boss Miss Frobisher. In every book, I introduce new characters to keep it fresh and keep people interested. In this book, there's a new character that seems to be a rival for Lily, both for her job and for Jim, so there's quite a bit of tension there.
"The other is a woman that Dora make a friendship with and it's the last person she would have expected to become friends with.
"The book ends with a big party that brings all of Lily's family and their friends together," explains Jo.
Writing the final chapter was a "bittersweet" moment for the author.
"It was really sad. It feels strange not to be sat at my desk and thinking about what Lily and Gladys are up to. Finding Beatties was an absolute marvel. It seemed the ideal setting for a group of characters because it was its own little world," says Jo, who attended this year's Wolverhampton Literature Festival.
Now she's put the Victory Girls to one side, Jo has been relishing the opportunity to write four-part serials for the likes of Women's Weekly.
"It's very different to writing a book where I would spend six months writing then three months editing and then more time doing promotion. These are done and dusted and being read in a shorter amount of time. I'm used to writing episodes from my time on The Archers," says Jo, who has also has written for Crossroads, Doctors and EastEnders.
Since the publication of her latest book, she has also done a number of talks at libraries and answered questions from readers.
"Those who have found the books have loved them. They're not the most gritty of sagas. I want people to have a smile on their face when they finish reading them and think 'that was entertaining'.
"It's a nostalgic look at a way of life and a way of shopping that has gone now. It's part of our social history. They are ordinary people living in extraordinary times, surviving with courage and humour. People had to make the best of things. I want people to find the books and love them," says Jo.
She will be giving a talk at Oldbury Library as part of its Live At The Library series on Friday, May 20 at 2pm. On Tuesday, June 21, Jo will be at Sedgley Library at 11am and at Coseley Library at 2.15pm.
Wedding Bells for the Victory Girls is available from booksellers now. See www.facebook.com/joannatoyewriter