JK Rowling chose her alter ego of Robert Galbraith by conflating the name of her political hero Robert F Kennedy and her childhood fantasy name "Ella Galbraith", the Harry Potter writer has explained on her alternative persona's official author website.

The author, who was outed last week as the writer of detective novel The Cuckoo's Calling, also confirmed that she has "just finished the sequel" – the first of a projected series featuring sleuth Cormoran Strike – which is to be published in 2014.

Amid the FAQs on the official Robert Galbraith author website, Rowling declared "I successfully channelled my inner bloke!" when editor David Shelley, who first read the novel without knowing who its true author was, said, "I never would have thought a woman wrote that."

The Cuckoo's Calling, shot to No 1 in the hardback fiction charts last week, selling 17,662 copies after Rowling was revealed to be its author, charting above Dan Brown's Inferno at number two, and Second Honeymoon by James Patterson at number three. In the overall UK book charts, it reached third place, behind paperbacks of John Grisham's The Racketeer at No 1, and Rowling's previous adult novel The Casual Vacancy, which also climbed rapidly following the news, at number two.

Writing on the Galbraith website, Rowling reaffirmed the line that the pseudonymous story "was not a leak or marketing ploy by me, my publisher or agent, both of whom have been completely supportive of my desire to fly under the radar. If sales were what mattered to me most, I would have written under my own name from the start, and with the greatest fanfare."

The decision to choose a male pseudonym was driven by a desire to "take my writing persona as far away as possible from me", Rowling said. By choosing as her hero a military man working in national security – taking a lead from former SAS solider and bestselling author Andy McNab – she created an "excuse not to make personal appearances or to provide a photograph".

"When I was a child, I really wanted to be called Ella Galbraith, I've no idea why. The name had a fascination for me. I actually considered calling myself LA Galbraith for the Strike series, but for fairly obvious reasons decided that initials were a bad idea," Rowling said.

"I know a number of soldiers and I'm close to two people in particular who were incredibly generous as I researched my hero's background," Rowling wrote. Her military contacts also helped to construct a fake CV for Robert Galbraith. "One of these friends is from the Special Investigations Bureau. So while Strike himself is entirely fictional, his career and the experiences he's had are based on factual accounts of real soldiers."

Rowling also reveals that lead character's first name "was a gift from his flaky groupie of a mother, is unusual and a recurring irritation to him as people normally get it wrong; we sense that he would much rather be called Bob."

The character of Strike's assistant, Robin, a temporary secretary, grew "largely out of my own experiences as a temp, long ago in London where I could always make rent between jobs because I could type 100 words a minute due to writing fiction in my spare time."

The book's title is taken from A Dirge, the mournful poem by Christina Rossetti which is a lament for one who died too young.

Rowling was "yearning to go back to the beginning of a writing career in this new genre, to work without hype or expectation and to receive totally unvarnished feedback. It was a fantastic experience and I only wish it could have gone on a little longer," she said. Most of the Harry Potter books are "whodunits at heart", she added, saying that she "loves detective fiction".

Its London setting was chosen above Scotland, where Rowling lives, because "you could write about London all your life and not exhaust the plots, settings or history," she said.

Rowling's identity as the author of The Cuckoo's Calling was leaked last week by a friend of one of her lawyers. At that point, the book had sold 8,500 English-language copies across all formats (hardback, eBook, library and audiobook), and received two offers from television production companies.

"The situation was becoming increasingly complicated," Rowling admitted, "largely because Robert was doing rather better than we had expected … but we all still hoped to keep the secret a little longer. Robert's success during his first three months as a published writer (discounting sales made after I was found out) actually compares favourably with JK Rowling's success over the equivalent period of her career."