Jack Reacher might feel like an unstoppable force of nature in Lee Child’s acclaimed “Jack Reacher” books, but one inspiration behind the character is surprisingly grounded. In a 2003 interview with January Magazine, Child revealed that Spenser, the no-nonsense private investigator from the late Robert B. Parker’s “Spenser” novels, was a key inspiration for Reacher. “The ‘Spenser’ series was influential in terms of Spenser’s impregnability and sense of self,” Child said.
One of Spenser’s key traits is his firm moral code. Despite operating outside of the law, Reacher also sticks to a moral code, going out of his way to protect the vulnerable in both Child’s novels and the Prime Video series, where he’s played by Alan Ritchson. And while Spenser doesn’t physically tower over most people like Reacher does, his experience as an ex-boxer provides him with an edge during dangerous cases.
Like Child’s “Jack Reacher” series, the “Spenser” books have been adapted for TV, with ABC turning them into a crime drama called “Spenser: Fire Hire.” Robert Ulrich of “S.W.A.T.” fame played the lead role in the show, which ran for three seasons between 1985 to 1988, when it was canceled. Speaking at the time, Parker claimed that ABC “mishandled” the show. “They slotted it wrong,” he said (via UPI). “But that’s not surprising when you’re dealing with people who know charts and numbers but nothing about film and story.”
Spenser is not the only fictional detective that inspired Lee Child when creating Jack Reacher
In his January Magazine interview, Lee Child revealed that Spenser was among the fictional investigators that inspired him when he was writing Jack Reacher’s first adventure, 1997’s “Killing Floor.” The other characters that formed Reacher’s DNA were Travis McGee, created by American mystery writer John D. MacDonald, and, perhaps the most famous detective of them all, Arthur Conan Doyle’s Sherlock Holmes.
In a 2025 interview with Men’s Journal, Child revealed that parts of “Killing Floor” were intended as a “conscious homage” to the iconic British sleuth. “I did an explicitly Sherlock Holmes thing where Reacher says to Finley, the cop, ‘I see that you’re divorced and you gave up smoking in April.’ That was Reacher deducing like Holmes.”
One lesser-known thing about Sherlock Holmes is that he’s actually got a lot of brawn to go with all those brains, something Child discussed when comparing the character to Jack Reacher during his sit-down with the men’s lifestyle magazine. “If you read the original Conan Doyle, Sherlock Holmes is a pretty violent fighter as well,” Child said. “He’s a street fighter. He is not just a brain. Same with Reacher.”
Like Spenser and Reacher, Holmes is no stranger to the small screen. His origins were recently explored in Guy Ritchie’s “Young Sherlock,” which changes a major piece of the detective’s lore. That’s not necessarily a bad thing, however — the Prime Video series was met with critical acclaim and it even made TVLine’s list of the best Sherlock Holmes TV shows of all time.