|Law & Order character|
|Time on show||2001—2005|
|Preceded by||Abbie Carmichael|
|Succeeded by||Alexandra Borgia|
|First appearance||"Who Let The Dogs Out?"|
|Last appearance||"Ain't No Love"|
|Portrayed by||Elisabeth Röhm|
Southerlyn joined the District Attorney's office in 2001 as an ADA, replacing Abbie Carmichael (Angie Harmon). She worked under District Attorneys Nora Lewin (Dianne Wiest) and Arthur Branch (Fred Thompson) and Executive Assistant District Attorney Jack McCoy (Sam Waterston). She is the longest serving junior ADA in the history of the series, though Casey Novak (Diane Neal) served for a longer period of time on Law & Order: Special Victims Unit.
She often disagrees and fights with McCoy over their trial strategies in cases where she sees the defendant's crime as a byproduct of social circumstances, such as homelessness or racism. She has an especially troubled relationship with Branch, a conservative who replaced Lewin as District Attorney in 2002.
She has a younger brother, as she mentions on episode "Married with Children".
Southerlyn is brought before the New York Supreme Court, Appellate Division's Disciplinary Committee in 2002 after promising to get legal help for a murder suspect who had taken hostages, to get him to release his prisoners. The man had a knife to a woman's throat and demanded a lawyer. Southerlyn, who happened to be in the area, volunteered to enter the store where the holdup was taking place, to negotiate the hostage's release. Since the man had asked for a lawyer, the committee attempts to paint Southerlyn's actions as fraudulent, since she was supposedly representing herself as his lawyer (which she denies), when she was in fact a district attorney. McCoy, who had once been brought before the committee himself, represents her. She is reprimanded, but keeps her law license.
In another episode, a murder suspect marries a gay witness who was supposed to testify against him and therefore claimed spousal privilege, denying crucial testimony. When McCoy starts a campaign to declare all gay marriages in New York illegal, Southerlyn refuses to help him.
Southerlyn is also portrayed as opposing the death penalty.
Röhm left the show in the middle of the fifteenth season, and made her last appearance in the episode "Ain't No Love." Her departure was noteworthy due to a surprising conversation between Southerlyn and Branch in the very last minutes of the episode. At the close of the show, Branch dismisses Southerlyn because he feels she is too sympathetic toward defendants, and that her emotions get in the way of looking at the facts. A stunned Southerlyn pauses for a moment, then asks, "Is this because I'm a lesbian?" In response, Branch assures her, "No. Of course not. No." Her final line is "Good. Good." This is the first and only instance that Southerlyn's homosexuality was ever mentioned,. In a previous episode she had shown discomfort over a case in which McCoy attempted to have same-sex marriage declared illegal in New York in order to get testimony from a gay defendant's spouse. Southerlyn had objected to this and refused to assist McCoy, but her leanings were never mentioned.
She mentions in "Shangri-La" that she dated a male college student while she was still in high school and that he is now a New York State Senator.
Series creator Dick Wolf later explained at the Television Critics Association press tour that he had consulted Röhm before scripting the scene — the only Wolf-authored scene in the installment — saying, "Do you want to go out with a bang or a whimper?" He characterized the scene as "unabashedly a water-cooler moment. And the fact that we're discussing it shows that I think it worked as a water-cooler moment." Wolf also noted the effectiveness of the device by reporting that the show's main online chat room "crashed 15 minutes after the show was over," although critic Alan Pergament joked in his column that the response came not because viewers approved, but "because many fans thought the out-of-left field ending was a crime."