Leonard's close reading of Ernest Hemingway (particularly For Whom the Bell Tolls) focused his attention on dialogue and point of view, but he claims to differ significantly from Hemingway: "I see more absurdity. I like people more. I'm more tolerant."

An acknowledged influence is the novel The Friends of Eddie Coyle (1972) by George V. Higgins, which utilizes dialogue and monologues as means of increasing realism. His portrayal of ordinary people (including law enforcers) in trouble follows Raymond Chandler and Dashiell Hammett.