During her first season on the show, she is paired with Executive ADA Ben Stone. During the prosecution of a rape case, he threatens to fire her after she fails to share key information she learned while interviewing a witness, which subsequently comes out in trial, jeopardizing the case. Stone eventually relents and refuses to accept her resignation, relating to her because of a key mistake he made early in his career. In another case, Kincaid temporarily resigns after it is revealed she and a judge that the DA's office is prosecuting were once lovers, possibly jeopardizing the case against him. After Stone resigns from the DA's office, she is paired with Jack McCoy, the new Executive ADA. In the two seasons they appear in together, she and the brash, competitive McCoy often butt heads over the social and political implications of their trial strategies, as well as McCoy's penchant for going to legal extremes to get a conviction. The two eventually form a close bond, however, and it is hinted in several episodes that the two become lovers. In the episode "Aftershock", she is one of the witnesses to a man being put to death after raping and murdering a young woman. Afterwards, she struggles with this, questioning whether or not the death penalty was a just punishment. Kincaid is killed just as she is considering leaving the DA's office; her car is struck by a drunk driver as she takes an inebriated Lennie Briscoe home from a bar. McCoy is haunted by her death, as evidenced by his intense, legally questionable efforts to prosecute a drunk driver and his indignation at being questioned about the circumstances of her death. Following her death, Briscoe re-enters Alcoholics Anonymous and remains sober for the rest of his life; it is implied that he feels his drinking was responsible for her death. In one episode of Season 6, "Corpus Delicti", Kincaid was played by Jill Hennessy's identical twin sister, Jacqueline Hennessy, in certain courtroom scenes. This was because Jill was filming in Baltimore for the crossover episode of , which was broadcast a few weeks later. Jacqueline Hennessy's performance was uncredited. Jamie Ross replaced Kincaid as McCoy's assistant.
Behind the scenes
The Kincaid character was written out after Hennessy expressed concern about being typecast as an "uptight lawyer". Kincaid was originally intended to be portrayed as paralyzed and leaving the DA's office for private practice after the events of "Aftershock". This was eventually changed to Kincaid's death, which wasn't officially confirmed until Season 9. Hennessy rejects claims she refused to come back for a follow-up episode: "I made it clear I wanted to come back. I found out they killed me off from a friend who watched the show and told me, 'Jill, they said you were dead!' I was surprised, because I always thought I would return. Even now, I'd love to come back for some bizarre flashbacks."
