In the mid-1980s Martini began his fiction-writing career. His first attempt at a novel, "The Simeon Chamber", was represented by an agent and sold to the New York publisher D.I. Fine within two weeks of its submission. It was published in 1987. "Compelling Evidence", his second novel, introduced his series character, attorney Paul Madriani, and was published by G.P. Putnam & Sons. A national bestseller, the novel earned Martini a critical and popular following. It was followed quickly by New York Times bestsellers "Prime Witness", "Undue Influence", "The Judge", and "The Attorney", each featuring the series character Madriani and his contrarian and irrepressible law partner, Harry Hinds.