Maggie McPherson is one of Michael Haller's ex-wives and is one of the top prosecutors in the state, earning her the nickname Maggie McFierce. McPherson was also the original prosecutor in the Louis Roulet case, but was removed from the case due to her conflict of interest with Haller. McPherson and Haller carry on a healthy relationship despite the awkwardness between them, and conceived a daughter during their marriage. McPherson's cooperation in a police sting operation led to the re-apprehension and imprisonment of Louis Roulet following his successful trial.