Gosalyn was the orphaned granddaughter of Professor Waddlemeyer, a brilliant scientist. She would later become a ward of the court, and was placed in an orphanage. After coming into contact with Darkwing Duck, they grew close, and he chose to adopt her, returning to the civilian identity he had previously left behind. Gosalyn is a tomboyish girl, and very energetic and spunky. Darkwing has stated that caring for her is more difficult than fighting evil, and his greatest fear is Gosalyn getting hurt. She has a desire to become either Darkwing's sidekick, or a hero in her own right. To this extent she would develop two superhero identities, the Crimson Quackette, and later, Quiverwing Quack. Her best friend is Honker Muddlefoot, who is aware of the true identity of Gosalyn's father.
According to an interview with the show's creator, Tad Stones, Gosalyn was partly based on what he believed his then two-year-old daughter would be like when she grew older.
Gosalyn starts out as spirited, caring, and brave. She has also shown to be pushy, spunky, and tomboyish. In the second cliffhanger, her personality has become sassy and sarcastic, and she gets very jealous of her father getting to go on adventures all the time. In the overall TV show, she is reduced to being mischievous, quick-tempered, loud, inconsiderate, and rebellious.
In the pilot episodes, Gosalyn is kidnapped from her orphanage by the nefarious Taurus Bulba. Her grandfather, Professor Waddlemeyer, had created a secret weapon, and Bulba believed that Gosalyn, as the last living relative, knew the arming code. Gosalyn would be rescued by Darkwing Duck, who hid her in his secret hideout atop a tower on the Audubon Bridge. Unbeknownst to Gosalyn, Prof. Waddlemeyer had secretly taught the code to her in a lullaby he used to sing to her each night. When she passed it on to Darkwing, the hero discovers that their meeting wasn't a coincidence, but destiny. Bulba learned of the secret and was nearly able to carry out his threat. Darkwing, with the help of his sidekick, Launchpad McQuack, was able to save Gosalyn and the world. Darkwing would choose to adopt her, and returned to his civilian identity of Drake Mallard and buy a home in the suburbs to live in. He often struggled with reigning in Gosalyn due to her energetic nature and his ego, but cared for her deeply.
One recurring theme was Gosalyn's desire to become a hero. In the episode "Trading Faces", Gosalyn would get the chance to become Darkwing Duck when the two switched bodies. In "The Quiverwing Quack", Gosalyn would take up the identity of Quiverwing Quack, an archery themed heroine. She would best Negaduck, but would become a target in order for Negaduck to regain his reputation as Public Enemy Number One. Though Gosalyn was usually tomboyish, in the episode "Slaves to Fashion", Binkie Muddlefoot would attempt to make her more ladylike and have Gosalyn dress up for a school dance. While there, she would fall under the influence of a spray made by Tuskernini, which made her act like a stereotypical lady.
In the Boom! Studios Darkwing Duck comic series, Gosalyn is attending a private school while her father has retired from crimefighting after the company Quackwerks takes hold of the city. When Honker is arrested, Gosalyn is the one to convince her father to retake the identity of Darkwing Duck.
While Darkwing investigates, Gosalyn manages to convince Launchpad McQuack, Darkwing's former sidekick, to return, despite the two ducks having had a fall out. Gosalyn and Launchpad manage to return to St. Canard just in time to rescue Darkwing from Quackwerk's crimebots.
Later on, during a confrontation with Taurus Bulba, who was behind Quackwerk's and its various schemes, Gosalyn manages to take control of the Gizmoduck suit. In the suit, Gosalyn, calling herself Gosmoduck, is able to destroy Taurus Bulba by shorting out his current body, but is believed to be killed in the resultant blast. Though Darkwing mourns briefly, he is overjoyed when it is revealed that Gosalyn survives. In the aftermath, she is allowed to keep the suit, but Darkwing restricts her usage to emergency situations. However, during the next adventure, the Gizmosuit is damaged and destroyed.
- Gosalyn looks like a younger version of Mallory McMallard from the Mighty Ducks animated series. Coincidentally, both characters play hockey.