She helps Dipper as he searches to uncover the secrets of Gravity Falls and to find an explanation for the strange situations they experience.

They are aided by Soos, the Shack's handyman; Wendy, Dipper's crush and the twins' co-worker; and other characters throughout the series.

The situations that they encounter include dealing with various supernatural or legendary creatures, like gnomes, cryptids, demons, aliens, minotaurs and the nefarious Bill Cipher.

The adventures of Mabel and her brother are inspired by the childhood of series creator Alex Hirsch and his own twin sister, Ariel.

[1] Mabel Pines is an energetic and optimistic girl from Piedmont, California, forced to spend her summer together with her Grunkle Stan in the fictional town of Gravity Falls, Oregon.

[8] Despite seeming as just being there for comic relief, Mabel is frequently instrumental in helping her brother solve the mysteries of Gravity Falls and played a pivotal role in all three of the fights that the twins have had against the main antagonist, Bill Cipher, to the point that Dipper says that he has no chance of defeating Bill without Mabel's help.

"[10] In the episode "Close Rick-counters of the Rick Kind" of the animated series Rick and Morty, twin boy and girl versions of protagonist Mortimer Chauncey "Morty" Smith, modelled after Dipper and Mabel Pines, are featured in the background of the episode in Easter egg cameo appearances, subsequently named as Mortipper and Mortabel Pines–Smith by Gravity Falls creator Alex Hirsch,[11] and featured as playable characters in the role-playing video game Pocket Mortys.

After the duo cameoed again in the third season episode "The Ricklantis Mixup", Mortabel returned on her own in the Gravity Falls: Lost Legends storyline Don't Dimension It by Hirsch and Serina Hernandez,[12] depicted as one of the many alternate versions of Mabel trapped in a pocket dimension, who join the primary reality Mabel in confronting the Anti-Mabel.

Upon their return, the Grunkles seal the rift and Mabel apologizes to Dipper for her past actions and gives a blue journal with a pine tree on it which she got from Mabipper (a composite version of the siblings) and hopes to start new adventures together.

She first appeared in the unreleased pilot made for Gravity Falls in 2010 by House of Cool Studios, which Alex Hirsch used to pitch the series to Disney Channel.