Grunkle Stan

According to the Season 2 episode "A Tale of Two Stans", Stanley and his six-fingered twin brother Stanford were born in Glass Shard Beach, New Jersey to Filbrick Pines and his wife Caryn.[9] The twins were raised Jewish but became atheists later in life, according to a secret web-page found in the aforementioned "Lost Legends" book.[10] Filbrick was a stern pawn shop owner, while Caryn, a pathological liar, worked as a phone psychic. The last name "Pines" was reportedly introduced in Ellis Island, but records of the family's original surname have been lost.[9] In their earlier adolescent days, Stan and Ford often scoured the beach and go treasure hunting. One time, they claimed an abandoned ship for themselves, dubbing it the "Stan-O-War". The twins worked on repairing this boat over time, hoping to sail it around the world one day.

As hinted in the Season 1 episode "Dreamscaperers", the boys were frequent targets of bullies, so Filbrick signed them up for boxing classes. Stan later used his boxing skills to save a woman named Carla McCorkle, nicknamed "Hotpants", from a robber. However, Carla eventually left him for a music-playing hippie.

In school, Ford was a straight-A student and a favorite of his teachers, while Stan was a prank-loving slacker who often copied his brother's test answers. On one fateful night, Stan wandered into a science fair hall and accidentally broke his brother's prize-winning perpetual motion machine, ruining Ford's chances of being accepted into the prestigious university West Coast Tech and straining their relationship. Filbrick disowned Stan, refusing to allow him back home until he could make real money.

Stan first took an interest in sales after seeing a billboard which glamorized the practice. Using various fake names over time, he started countless companies promoting "revolutionary" products that all turned out to be dysfunctional and poorly made. He was ultimately chased away by angry mobs each time the flaws in his products were discovered and banned in a majority of American states. He was also once arrested in Colombia and placed on the United States No Fly List, both for reasons unknown.

Stan came to Gravity Falls upon receiving a postcard from Ford, now a Ph.D. graduate of the lackluster Backupsmore University, who used his research grants to build a house there and investigate the world's largest concentration of supernatural anomalies. In a dream, the demon Bill Cipher persuaded Ford into building an interdimensional portal with the aid of fellow Backupsmore alumnus Fiddleford McGucket (known in the present as local hillbilly "Old Man" McGucket) underneath Ford's house. In a test, Fiddleford survived an incident involving a gravity anomaly, leading him to quit the project, construct a ray gun to erase specified memories, and found the Society of the Blind Eye: an underground secret society dedicated the erasure of memories of townsfolk in Gravity Falls to keep the status quo. When Ford demanded answers, Bill revealed his true intentions, prompting Ford to contact Stan for help.

After Stan arrived, he learned that Ford had hid two of his three journals documenting his supernatural findings and explaining how to operate the portal, entrusting the first to Stan in hopes he would agree to bury it "as far away as possible". Outraged that Ford did not call him to reconcile, Stan wanted to burn the journal. In a brawl, Stan threw Ford into the accidentally activated portal, which then ran out of fuel and deactivated. Stan learned to his dismay that he could not reactivate the portal without all three journals.

With money running low, Stan went into town to buy some supplies to run away again, but locals mistook him for Ford and requested for a tour of the house, offering money. Stan agreed, adopting the name "Stanford" as his own. He tried to impress them with some of Ford's inventions but failed, then won over the tourists with his first fake attraction. Stan subsequently converted the house into a tourist trap of fake attractions, dubbing it initially "The Murder Hut", but later renaming it "The Mystery Shack". He even faked his death as Stanley in another state to avoid further pursuit from the police. For the last 30 years prior to the start of the series, Stan has continued to sneak into the lab at night to try reactivating the portal so he can rescue Ford.

For most of Gravity Falls, Stan is shown to be a simple, miserly character who devises mischievous, comical plans to earn money from Mystery Shack tourism. Despite his greed, he is genuinely protective of his great-nephew Dipper and great-niece Mabel, whose parents have asked him to watch the twins for the summer. He also pretends to be unaware of Gravity Falls' supernatural oddities and engages in a bitter rivalry with Gideon Gleeful: the malevolent 10-year-old proprietor of another tourist trap dubbed the "Tent of Telepathy" who is bent on claiming the Mystery Shack for himself. Unbeknownst to Dipper and Mabel, Stan has the first of Ford's journals. By the end of the first season, following Gideon's arrest for causing mass destruction and fooling his tourists in the episode "Gideon Rises", Stan obtains all three journals and tries using them to reactivate the portal. He finally succeeds in reactivating the portal and bringing Ford back to his home dimension near the end of the second season episode "Not What He Seems". The brothers then tell their story to Dipper and Mabel and struggle to reconnect over subsequent episodes because of the different paths their lives have taken.

In the last few episodes, the prophesied apocalypse dubbed "Weirdmageddon" begins, Bill Cipher captures Ford, and Stan takes refuge in the Shack, enchanted by Stanford's unicorn spell. McGucket finds him and invites into the Shack an army of the series' supporting characters. Stan is jealous of Dipper, Mabel, and his employees Soos and Wendy wanting to save him even though he feels responsible for the apocalypse.

After a battle with Bill's demons using the "Shacktron", a fighting robot built from the Shack itself, the heroes unfreeze the rest of the townsfolk in Bill's fortress, the "Fearamid". To stop Bill, Ford draws on the floor a prophetic diagram bearing ten symbols around a wheel. Each symbol represents something related to one of the major characters of the series. Each individual stands on their symbol except Stan, who demands that Ford thank him. Ford gives him his request, but Ford corrects his grammar shortly after. The brothers fight until Bill finds them, captures the Pines family, and turns everyone else into tapestries. Dipper and Mabel distract Bill and escape their cell while Stan and Ford are locked in another cell, where they finally reconcile.

Ford reveals that Bill needs a secret equation stored in his mind to spread the Weirdmageddon effect all over the world and that luring Bill into his mind, then erasing it with McGucket's memory gun, would erase the demon from existence. However, this is seemingly impossible, as Ford has a metal plate in his skull to stop Bill from accessing his thoughts. Stan volunteers to have his mind erased, and the brothers switch clothes. When Bill returns, the disguised Stan agrees to his plan, tricking Bill into entering the wrong mindscape.[11] As Ford erases Stan's memory, Bill is punched into non-existence by Stan's mindscape self, who realizes that his purpose in life was to protect his family before he burns in silence.

After Gravity Falls returns to normal, Stan awakens without any memories until his family and friends revive them. On the last day of the summer, Stan and Ford make plans to live out their dream of sailing around the world, this time to find more anomalies. Stan promotes an enthusiastic Soos to manager of the Shack and is last seen in a flash-forward at sea with Ford as they deal with an anomaly aboard a ship dubbed the "Stan-O-War II".

Stan is based on Alex Hirsch's own grandfather, also named Stan. Both share the characteristics of being big, barrel-chested guys whose clothes have popped-undone buttons; both also wear a gold chain and gold rings.[12]

Stan originally looked considerably different than he does in the show. In conceptual art, Stan was shorter, did not have his shoulder pads, and had a pointy pink nose instead of a big orange one. His face also more resembled a puppet than a grizzled old conman.[13] This version of the character was seen in an unaired unofficial pilot of the show, which was low budget and a pre-production test version based around the aired pilot episode "Tourist Trapped."

Along with Dipper and Mabel, Stan has appeared in almost every episode of the series. He was featured in the Gravity Falls series of shorts entitled "Dipper's Guide to the Unexplained", as well as a short ("Stan's Tattoo") in which the twins investigate the mysterious tattoo on Stan's shoulder. In "A Tale of Two Stans", it's revealed that it was not a tattoo but a burn scar.