She was portrayed by actress Elizabeth Hendrickson from May 29, 2018 until June 18, 2019.
Former Y&R Alum, Elizabeth Hendrickson, who has been previously Daytime Emmy-nominated, will begin her GH run as a prosecutor in Carly’s (Laura Wright) case. Fans have been very excited about the addition of Hendrickson to the ABC daytime drama series, because she will be reunited with many of her former castmates from All My Children and Young & the Restless, including Billy Miller (Drew), William deVry (Julian), and more.
Shelly Altman, co-head writer of General Hospital, told Soap Opera Digest, “Margaux doesn’t believe that Carly was insane, and of course, she’s right. She doesn’t like anyone using the court to their advantage in this way.”
In August 14, 2018, Executive Producer Frank Valentini was interviewed by Michael Fairman. He revealed he brought on Elizabeth Hendrickson (Margaux) as a potential love interest for Drew. He said "I knew her work from All My Children and The Young and the Restless, and she is a phenomenal actress and we are really lucky to have her. Margaux has got the flash drive with Drew’s memories on it and that is an important piece of information to have."
On June 6, 2019, Hendrickson confirmed on her Instagram page that she is leaving GH. She made her last appearance on June 18.
Margaux Dawson is the new District Attorney in Port Charles. Like her predecessors at the DA's office, she is determined to convict Sonny Corinthos and his organization for all of their crimes.
Margaux has met Drew Cain, and as of July 24, she is in possession of the missing drive containing all of his memories. On August 17, they shared their first kiss at Charlie's. Soon afterwards they begin dating.
Margaux seems familiar to Dr. Kim Nero, like she has seen her before.
On August 21, it's revealed that Margaux was born as Margaux Marino, her father wasn't around in her early life as he left her and her mother when she was two years old. She grew up in Princeton, New Jersey, and entered in middle class, public schools and was at the top of her class. She joined NYU and soon she enrolled herself in law school at Stanford law and graduated with honours. After law school she worked as assistant DA in Oakland, California, which is near San Francisco. Two years later, she was appointed as the new DA of Port Charles.
In September 11, 2018, it's revealed that Margaux's father was somehow involved in the mob and he was killed because of it. In September 21, it's revealed that thirty years ago her father, Vincent Marino, was Joe Scully's criminal defence lawyer and that he was killed by Sonny before being buried in Croton under orders from Joe. Unbeknown to Sonny at the time Vincent's corpse was unearthed by his father Mike Corbin so it would be reburied underneath Charlie's Pub during it's construction.
She had one brief marriage to David Dawson that ended after a year since she felt he had a lack of imagination as he only wanted to maintain the status quo while she wanted more so they parted as friends and she is still using his name to this day.
On July 17, Margaux met Drew Cain and on July 24, she found the missing drive containing all of his memories in the lost and found box at the Metro court. In early August, thanks to Jason, Margaux was given all the evidence needed to exonerate Carly and to convict Nelle for her numerous crimes; particularly killing her ex fiancé Zachary Grant before she came to town, framing Carly, and recently attempting to have her thought-to-be husband Michael murdered. She continues to bond well with Drew, without him having any knowledge that she has the key to his past. On August 17, at Charlie's, after Drew refused to help Margaux in her plot to take down Sonny, she kissed him before she walked out. Drew followed her and questioned her about the kiss. After back and forth arguments, they confessed that they are attracted to each other and they agreed on a date.
On August 22, they went out on a date at the Floating Rib where they ran into Carly and Jason, Carly accused her of using Drew to get to Jason to which Margaux rebuffed and claimed otherwise. Later when Drew took Margaux back to her room, she excused herself to change her blouse, and when she returned she saw Drew holding a flash drive. She panicked and claimed it contains evidence for a case, but he guesses that she's lying. She shows him the photos on the flash drive of her as a kid in her computer. He apologizes. She wonders if he got himself invited in just to search her suite. After a back and forth argument, Drew decides to leave but as he's about leave, Margaux stops him and they kiss. Later when he leaves, she takes a flash drive labelled Anamnesis Project out of her vault.
In September, after learning that the dead body that was found beneath Charlie's Pub was her father, Vincent, she became even more determined to nail Sonny for his murder. In October 11, Margaux revealed to Drew that she has the missing drive and she offers to give it to him in exchange for his help in taking down Sonny.
On December 10, 2018, Margaux gives Drew the flash drive containing his memories. At first he doesn't want to take it, but Margaux forces him to take it.
On June 18, 2019, Margaux left town, 12 days after threatening Shiloh.