At the time of first meeting her, it is quite clear that Dr. Fancyfree is quite frustrated with her client, Denzel Crocker, and his insane belief in fairies that usually results in him flipping out in spasms and destroying her office. She decides to use hypnosis, even though it goes against what she was taught, and manages to cure Mr. Crocker. She quickly throws him out afterward.
She has brown colored hair and purple colored pupils. She wears a tight red blouse with a black miniskirt, rectangular shaped glasses, and black earrings. Usually she keeps her hair down, but when she starts to get serious, she ties her hair into a bun.
Mr. Crocker visits her at her office at the psychiatric institute, begging her to cure his unhealthy obsession. Dr. Fancyfree is frustrated by him, and decides to take drastic measures by hypnotizing Crocker. This works, and Mr. Crocker is cured and released. However because Mr. Crocker was cured, the power to Fairy World is lost as Crocker was the fairies' power source due to his constant fairy spasming. After her hypnosis technique proves successful, she offers to use it on another client, The Mayor of Dimmsdale's pet and good friend Chompy the Goat (who is still mad at the Mayor due to him finding out the Mayor ate at a goat meat eating convention). She tells the Mayor that she uses a safe word that would never be said to the person being hypnotized normally, as it will release them from the hypnosis. This is to protect her from possible lawsuits.
Timmy Turner discovers this and after telling them, he, Cosmo, Wanda, and Jorgen start tossing out things like, "You're extremely handsome" and "I love you" But soon Timmy figures out Mr. Crocker's safe word, "You're the best teacher ever!", and says it to him causing Crocker to believe in fairies again. It was Mr. Crocker's belief in fairies that powered Fairy World due to his constant spasming, and without it, fairies would lose their magic. But with Dr. Fancyfree around, Mr. Crocker could get cured again. So Timmy shows up to her office and flies outside her window with Cosmo, Wanda, and Poof in plain view. She then loses her mind and starts to believe in fairies, proeeding flip out and spasm to almost no end much like how Mr. Crocker does whenever he sees fairies, wrecking her office as Mr. Crocker encourages her to continue (saying "YOU GO GIRL!" to her as she flips out).
It is unknown about what happened to her after that, though it is possible that she and Crocker started working together to exploit Timmy's fairies. This is never shown to be true.
In the Swedish dub, her name is Doktor Frida Fågelfri, "Fågelfri" means "Fancyfree".
Her appearance and voice are somewhat similar to those of Tina Fey.
When Fancyfree reacted to the presence of Timmy and his fairies, it was similar to how The Joker first met Harley Quinn in the Batman episode, "Mad Love".