- "When you're a kid, you think that you'll always be... protected, and cared for. Then, one day, you realize that's not true. If you open your eyes, you will see what we're going through. 'Cause when you're alone as a kid, the monsters see you as weaker. You don't even know they're getting closer. Until it's too late."
- ―Stanley Uris in It: Chapter One (2017 film)
As a child, he was good friends with Bill Denbrough, Ben Hanscom, Richie Tozier, Eddie Kaspbrak, Mike Hanlon and Beverly Marsh. He joined the Losers' Club at the same time Richie did, walking in on Bill, Eddie, and Ben as they were building the dam in the Barrens.
Stan was one of the only Jewish kids in the school, something which resulted in severe torment from Henry Bowers and the other bullies. Not only do the bullies berate Stan about his religion, but Richie constantly jokes and makes fun about it as well. Stan was a very methodical and mature child, particular about always keeping clean and (In 2017 Film) suffers from OCD. He is also the most skeptical and fearful of It, not being able to accept the happenings around him at first and terrified to believe that It is real. He has a very set way of approaching life, so the appearance of It in his life turns everything around and confuses and terrifies him.
Stan's favorite hobby is bird watching. He can often be seen with his bird book (something that is later used to fight against It).
In the novel, Stan's family is Jewish but they do not follow the practice very strictly (Stan did not even know what it meant to be kosher). However, in the 2017 film his father is a Rabbi. He seems to have a close relationship with his parents, although they seem to put a lot of pressure on him. Bill and Eddie state that it is typical for Jews to "have big noses and a lot of money", but that Stan "had a normal nose and never seemed to have enough money."
Encounter with It
Stan is reluctant to tell the others about his encounter with It until later, when he is helping Beverly wash the blood-stained rags from her own encounter with It at the laundromat. Like Richie, he believed that his encounter had been a dream at first. He even told the Losers that he attempted to convince himself what he had seen had been an epileptic fit of some sort, as it was easier to come to terms with than the reality of what he had seen.
The appearance of It for Stan happens one day when he is bird watching in the park where the Standpipe was. When he looked at the Standpipe, he said that to him it had appeared to be floating. He then heard the door of the Standpipe open, and, curious as to how it could have opened on its own, he decided to venture and take a look. As he ascended the stairs into the Standpipe, he heard footsteps and then saw shadows above him. The door behind him slammed shut. A voice began to call to him, claiming that they were "the dead ones", the children that had drowned there. Reaching for his bird book, he began to chant as many names of birds has he could remember, which resulted in the door opening as he chanted more, finally allowing him to go back out into the park. However, when he turned his back, he saw the body of a dead person, beckoning for him to come to them.
Stan also has intense difficulty accepted the reality of It targeting the Losers when Mike brings his father's photo album of pictures of Derry throughout history. As the group looked through the pictures, the images inside came alive as they did when Bill and Richie had looked through Georgie's photo album, and Pennywise began to try to harass them. After the book was closed, Stan was unable to deal with what he had just seen. He repeatedly began saying "no" and denying what he had seen, until Bill told him that they had all seen it. Stan says, however, that he did not want to see it.
The Blood Oath
While in the sewers, Stan was the most uncomfortable and terrified. He said that he could, in fact, deal with the fear he was experiencing. What he could not deal with was being dirty and not knowing where he was.After the kids escape the sewers after defeating It for the first time, Stan leaves the group momentarily to retrieve a discarded Coca Cola bottle. He breaks it on a nearby rock, and uses a shard of the glass to cut the palms of all the Losers. Stan makes a joke about cutting his wrists instead of his palm (a foreshadowing to his death as an adult), and Bill even considered trying to stop him as he was unsure whether Stan was joking or not. After all of the Losers' palms have been cut, they hold hands in a circle and make a pact that if It ever came back, they would all return to Derry to fight it once more and defeat it once and for all.
As an adult, Stan is in a happy marriage with a Jewish woman he met at a college party, Patricia Blum. Stan has an extremely successful job as an accountant in Atlanta, Georgia and it is noted that Patricia is very proud of their large house. Patricia and Stan had been trying to have children for a long time, but to no avail. They went to many doctors to check if they had any problems or diseases, but it showed that they were both perfectly healthy. However, although they did not know the cause of it, both Patricia and Stan knew that the reason they couldn't conceive a child was not Patricia's fault, but rather something in Stan that was preventing it from happening.
When Mike calls Stan to tell him that It had returned to Derry and that they would all have to come back to fight it, Stan cannot comprehend this at first. His memories rush back almost right away, unlike the others, and Stan is filled with the same intense fear he battled as a child. After the phone call, he tells his wife that he is going to take a bath (something she notes is very unusual, as he was very regimented about his bathing times) and locks himself in the bathroom.
Patricia quickly realizes that something is very wrong and begins to panic especially after Stan does not open the bathroom door to her or answer her calling. Finally, she gets a spare key to the bathroom and unlocks the door to find Stan in the bath tub, both arms slit vertically from his wrist to the crook of his elbow and also horizontally at the wrist, making T's. She also sees that with whatever last bit of strength he had, he had written the word "IT" on the bathroom wall in his red Dark own blood. And in conclusion He does not return to Derry, Maine to help the Losers fight It.