Twilight and her dragon assistant Spike become close friends with five other ponies: Applejack, Rarity, Fluttershy, Rainbow Dash, and Pinkie Pie.

Each of the ponies represent a different aspect of friendship, and Twilight discovers herself to be a key part of the magical artifacts known as the "Elements of Harmony".

Twilight also helps to defeat villains such as Discord—the spirit of chaos—Queen Chrysalis—the leader of the changelings—and King Sombra—a dark unicorn seeking to take over the Crystal Empire.

In the season three episode "Magical Mystery Cure", she fixes a spell by famed wizard Star Swirl the Bearded and graduates from her studies with Celestia.

While Twilight and her friends are preparing Equestria's first Friendship Festival in Canterlot, the city comes under attack by the army of an evil conqueror called the Storm King, led by his second-in-command, Tempest Shadow, a unicorn with a broken horn.

They help her win the election for Princess of the school's Fall Formal, and together they defeat and reform Sunset when she tries to use the crown to brainwash the students into becoming her personal army to invade Equestria.

In the second film, Twilight returns to the human world with Spike when Sunset uses her magic book to warn her of the emergence of the Dazzlings, creatures from Equestria who have the ability to use their singing voices to manipulate others.

Twilight makes a cameo appearance at the start of the film, during an imaginary sequence depicting a playtime session between Sunny Starscout, Hitch Trailblazer, and Sprout Cloverleaf that goes awry when Sprout acts as if Rarity were an evil unicorn due to prejudices between the three pony races having resurfaced following Twilight's implied passing.

Her cutie mark appears in the film as the symbol in both Sunny's diary and a window in an abandoned Zephyr Heights airport.

In the next film, My Little Pony: Equestria Girls – Legend of Everfree she is revealed to have become a backup vocalist in the Rainbooms and obtains telekenisis as her geode power.

[17][18] Hasbro wanted to retool the My Little Pony franchise to better suit the current demographic of young girls, similar to how Michael Bay's film Transformers had helped boost the new Transformers toy line[19] According to Margaret Loesch, CEO of Hub Network, revisiting properties that had worked in the past was an important programming decision, which was somewhat influenced by the opinions of the network's programming executives, several of whom were once fans of such shows.

[20] Hasbro's senior vice president, Linda Steiner, stated the company "intended to have the show appeal to a larger demographic", with the concept of parents "co-viewing" with their children being a central theme of the Hub Network's programming.

[21] Central themes that Hasbro sought for the show included friendship and working together, factors they determined from market research in how girls played with their toys.

[25] When she pitched to Lisa Licht of Hasbro Studios, the latter was not very interested, but she showed Faust one of the company's recent My Little Pony animated works, Princess Promenade, "completely on the fly".

[19][24][26] Faust agreed to take the job as long as she was able to move away from the "silliness of [My Little Pony's] predecessors and their patronizing attitudes towards young girls".

After developing Friendship Is Magic's pitch bible, Faust asked Strong to help her complete it by voicing Twilight, Pinkie Pie, and Applejack or Rainbow Dash.

Faust had expected Strong to book the role of Pinkie Pie as she was similar to Bubbles, who the actress had voiced in The Powerpuff Girls.

[32] Rebecca Shoichet initially became involved with the series through frequent collaborator Daniel Ingram, who composed the songs for the show.

Originally, she had an cutie mark with an heavenly design that highlighted her royalty and mystical knowledge, which were later reflected in her purple color.

[36] Like other ponies, Twilight's body does not feature shading; her mane and tail lack depth and are generally fixed shapes, animated by bending and stretching them in curves in three dimensions and giving them a sense of movement without the cost of individual hairs.

Isabelle Licari-Guillaume insisted that Twilight is a "convincing figurehead" for nerd culture and a major factor in the success of the series.

[39] Theresia Sitinjak, a writer at Diponegoro University, stated Twilight represents the American cultural values of individualism, altruism, and industry[40]—reflected in several of her character traits, including her optimism, friendships, and high standards.

[41] Ethan Lewis, from Den of Geek, asserted she is "one of the more complex characters of this show" because she "embodies many contradictions"; for example, he wrote that despite being scientific, logical, and reasonable, Twilight's element of harmony is magic.