Adam Donner is a former assistant district attorney of Starling City. He worked under Kate Spencer, the district attorney, and was the late Laurel Lance's ex-boss. Adam lost his job after attempting to lure out Helena Bertinelli so that she could be arrested, which led to him being taken as part of a hostage crisis at the courthouse.
Moira Queen's trial
Adam then served as the lead prosecutor in the trial of Moira Queen. Before the trial began, he informed Laurel that he had a "trump card" that will turn the jury against Moira; her affair with Malcolm Merlyn who is the biological father of Thea Queen. While cross-examining Thea, he suddenly collapsed in the courtroom, an unwitting victim of Cecil Adams' newest scheme to spread Vertigo throughout Starling City. He was then kidnapped by Cecil, who forced him to beg, on a live TV broadcast, for another injection of Vertigo to ease his withdrawal symptoms. Adam was later rescued by the Arrow.
Subsequent investigations and dismissal
When Laurel looked into Maya Resik's death, Adam refused Laurel's request to investigate Sebastian Blood, saying it would jeopardize his career. After Laurel was arrested for possession of drugs, he told her that charges will not be filed, but fired her from the DA's office.
Several weeks later, Adam reinstated Laurel as an ADA to prosecute Frank Bertinelli. This turned out to be a ruse to lure out Helena Bertinelli so the police could capture her. However, this backfired, resulting in a hostage crisis at the courthouse which was eventually defused by the Arrow and the Canary. Afterwards, Adam was fired as ADA.
Kate Spencer stated to Laurel that Adam did not have the authorization to rehire her but Laurel was able to parlay her own knowledge of the trap and its disastrous consequences into keeping her job.