Dawn arrived in Port Charles in 1989 and became a student nurse at GH. It was soon revealed that Dawn was actually the long lost child of Monica Quartermaine and David Langton. Dawn was excited to find a new mother but was also excited to find love with Ned Ashton. Ned was so taken with Dawn that he bought her Spoon Island and the house on it called Wyndemere.

In 1990, Dawn and Ned became engaged. Dawn, however, was privately infatuated with young con artist Decker Moss, whom Tracy Quartermaine enlisted to help break the couple up. On Ned and Dawn's wedding day, it was revealed that Ned had once had an affair with Dawn's mother Monica! Dawn felt betrayed by both her true love and her mother, and ran away in Ned's Ferrari, which had been decorated for the wedding. She left town in the company of Decker

In 1991, Dawn and Decker returned to Port Charles. Dawn was hoping to make amends with her mother, and both shared in the excitement of Dawn's plans to marry Decker. While Decker was out of town dealing with a gambling problem, Ned forged a letter he'd left and tried to pass it off as a Dear Dawn letter, but Dawn gave him a slap instead of reconciliation.

Dawn moved in with friend and fellow student nurse Meg Lawson to a home at the Willow Stone condo, paid for by Monica. Dawn fell ill after exposure to contaminated water there. She was cured, and not long after Decker returned to town. They were happier than ever.

Tragically, Edge, a con artist hoping to break up Decker and Dawn to get his hands on Dawn's money, was tied up with the two by old enemies. Body Heat, the club Decker and Edge co-owned and all 3 were tied up in, was set on fire. Edge freed himself and bludgeoned Dawn and Decker with a lead pipe. Dawn didn't survive. Edge had placed the pipe in Decker's hand, but was cleared when a videotape surfaced, revealing the killer to be Edge Jerome. Before Edge could be arrested however, he was killed by his own enemies and his severed head was found in a dumpster. Monica was devastated, and Decker left town.

Dawn was last mentioned when Alan reminded Monica of how he had accepted Dawn, while Monica was refusing to accept his long-lost daughter, Skye. After the mention of Dawn's name, Monica agreed to try.