Trixie is a blue-furred Unicorn, with a slightly scruffy tail and smoothed out mane, both ice blue. Her Cutie Mark is a magic wand with a light blue magical aura circling it like a moon.
She often wears a magician's hat and cape, both of which are lavender and are covered in blue and yellow stars.
Trixie is boastful, and prideful of herself, often talking in the third person and referring to herself as "the Great and Powerful Trixie". This is her more prominent trait, stemmed from in a way her profession as a traveling magician. This pride does sometimes blind her to her actions, such as when she accidentally teleported the Tindalos to Beach City, she was more thrilled about her feat in magic than the danger she caused until after being told up front.
Though often confident, she does fall into panic and horror fairly easily if placed in a dangerous situation, and is somewhat prone to sarcasm.
She had two notable encounters in Ponyville prior to the series both described by Pinkie Pie: the first encounter was with her traveling show arriving in town and showing up Rarity, Applejack, and Rainbow Dash just before an Ursa Minor came to Ponyville.
Her second involvement with Ponyville had her return with a magic-sucking amulet, turning her evil and going against the entire town. However it was Twilight Sparkle who stopped her, and apparently they both performed for Celestia after this.
Her first true appearance in My Little Universe came in Season 2, with her being apart of the Talent Contest of the Gifted, being openly welcomed back into the show. She had a brief encounter with the Crystal Gems before the show, boasting about how much stronger her magic was compared to Gem magic. Her performance during the show involved numerous stars and magical beams, which itself was just impressive enough to tie with Sardonyx. In the end, she agreed to perform with them for the finale, and congratulated the Gems, but promised it won't be so easy next time they would meet.
Her role becomes more prominent throughout Season 7 as a supporting character. After several failed attempts to make a new friend, Starlight Glimmer and Pink Diamond meets and befriends Trixie. Twilight expresses uncertainty in their friendship due to their respective pasts. When Trixie plans to put on a magic show in Ponyville to display her repentance, Starlight volunteers to be her assistant. As they spend time together, Trixie admits to Starlight that she has always been jealous of Twilight. When Twilight eventually confronts Trixie and Starlight, Trixie reveals that she partly became friends with Starlight to one-up Twilight, much to Starlight's horror. After Trixie expresses her own heartbreak over her and Starlight's falling-out, Starlight assists in Trixie's magic show—performing a trick previously only carried out by pony magician Hoofdini—and the two new friends make amends.
She appears numerous times throughout the season, mostly with Pink Diamond and Starlight Glimmer and practicing her magic. During one of these practices, she and her friends were cornered by a pack of Tindalos, who she teleports Sniper's Father to Beach City by mistake as his eyes reminded her of Sapphire. After the big attack, she accidentally revealed her involvement with their appearance, and she was punished by cleaning up the mess they left behind.
She also joined them with aid during the two-parter finale.