Films:
Pinkie Pie is the head of the party planning committee at Canterlot High School.
Twilight Sparkle meets her in the gymnasium to sign up for the Princess of the Fall Formal ballot. At first, Pinkie is on unfriendly terms with
Fluttershy and
Rarity, but thanks to Twilight, she and Twilight's other new friends realize that
Sunset Shimmer turned them against each other. The friends reconcile and work together to help Twilight become Fall Formal Princess.
When Twilight starts explaining who she really is, Pinkie accurately guesses on "a hunch" that Twilight is a pony princess from an
alternate world on a mission to retrieve a "magical element".
When Sunset puts on Twilight's crown and transforms into a "raging she-demon", Pinkie Pie briefly channels the element of laughter and gains pony-like attributes. After Sunset Shimmer's defeat, Pinkie tries to follow Twilight through the portal, but the portal closes before she can.
Pinkie Pie reappears in
Rainbow Rocks and its tie-in animated shorts playing the drums in her friends' band, the Rainbooms. She first appears in the film helping her friends make a poster for the
CHS Musical Showcase, using cake frosting instead of paste. She later hosts a slumber party at her house that all of her friends attend.
When the Rainbooms are at each other's throats over who is to blame for their predicament in the climax, Pinkie thinks that being in the Rainbooms is now the opposite of fun. After Sunset gets the Rainbooms to see their mistake and forgive each other, Pinkie is ecstatic that the band is back together.
Pinkie Pie appears briefly at the Sweet Shoppe with her friends, waving to
DJ Pon-3 when she enters. Her waving is notably faster than the others, despite everything being in slow motion.
Pinkie Pie appears with her friends at the music store and suggests instruments for
Rainbow Dash to buy, including a banjo and a tuba. Towards the end, after
Trixie vows for revenge against Rainbow Dash, Pinkie Pie pops back at the entrance and "corrects" her out of context, making a gag at Trixie's expense.
In the animated short Pinkie on the One, Pinkie Pie displays both the talent and energy of an expert drummer, which she expresses through her baking and artistry. She has so much energy that she cannot stop drumming with her eating utensils in the cafeteria. When Rarity suggests finding an outlet for Pinkie's energy, Rainbow Dash places her in front of a drum set. Pinkie performs a wild, fast drum solo and she transforms into her half-pony form.
Pinkie appears in the music room with the other Rainbooms. She is the one to suggest that Rarity pick up the more mobile keytar (calling it a "guitarkey") in favor of the bulkier grand piano.
Pinkie appears with her friends when Applejack bargains with
Flim and Flam for her bass guitar, at one point gleefully playing with a rocking horse.
Pinkie sings the titular song with her friends and helps set up the auditorium for the Rainbooms' performance, briefly suggesting a Hawaiian luau theme.
Pinkie sings the song Perfect Day for Fun with her friends and enjoys the Canterlot High School carnival, mostly in Rarity's company.
Pinkie briefly appears in a flashback putting her hand on Sunset Shimmer's after her defeat in the first film.
Pinkie performs the song with the Rainbooms, singing a verse in the style of '80s techno-pop, and happily interacts with Sunset Shimmer.
Pinkie Pie appears again in Friendship Games, competing in the games against
Crystal Prep Academy as part of Canterlot High's Wondercolts team. She participates in the Academic Decathlon, winning the baking contest after creating a replica of the Mona Lisa inside a giant cake. She is paired up with Rarity during the speedskating portion of the Tri-Cross Relay, beating
Sunny Flare and
Lemon Zest.
Pinkie Pie is the first of her friends to realize that the
Twilight they meet during the Friendship Games is from the human world and not Equestria. She helps break the ice between Canterlot High School and Crystal Prep Academy by livening up the school's tense welcoming party. Her joy at seeing the two rival schools mingling causes her to pony up, but her magic is inadvertently drained by Twilight's magic-detecting device. She later regains her magic to empower Sunset Shimmer and return Twilight to normal after she transforms into Midnight Sparkle.
In this short, Sunset experiments to see how magic operates in the human world. Once Pinkie begins drumming, she ponies up and causes balloons of different shapes and colors to shoot out of her drum kit. The balloons cause Sunset to have a static electricity reaction.
In this short, Pinkie Pie constantly ruins Rainbow's attempts of not being seen when she's spying on Crystal Prep Academy's sports team.
Pinkie makes a brief cameo at the beginning of the short skipping out the school entrance.
Personality:
Pinkie Pie shares many of her pony counterpart's character traits and cartoonish quirks, including having a very cheerful and sociable personality and performing various comedic gags. At one point in the first film, she picks one of the balloon patterns off her skirt and inflates it like an actual balloon.
In the second and third films and tie-in animated shorts, Pinkie displays more cartoonish gags. She has a tendency to skip instead of walk normally, she has a refrigerator stocked with cans of whipped cream, and she tends to pop out of random places such as a locker and air vent. Though she doesn't own a party cannon in the first film, she uses her kick-drums as a party cannon in the second film, and she owns two party cannons by the third film.
Above all else, Pinkie's strongest trait is her love of spreading joy to others. She throws a party for the aloof Crystal Prep students in Friendship Games, and this desire to make others happy drives her to establish a glee club in the My Little Pony Annual 2013.