As a child, his best friends were Big Bill Denbrough, Stan "the Man" Uris, and Eddie "Spaghetti" Kaspbrak. He was also friends with Beverly Marsh, Ben Hanscom, and Mike Hanlon. Like the others in the Losers' Club, he looked up to Bill, and he was cited as the one who 'understood Bill better than anyone'. He also thought Beverly was pretty, but only perceived her as if she was the same as any other male friend. He also often teases the other Losers, especially Eddie, calling him "Eds" and "cute" against his protests.
He wore thick black glasses and had huge front buck teeth which earned him the name "Bucky Beaver" by others in his school, though he was later dubbed "Trashmouth" by the Losers due to his foul language and loud mouth that often got him into trouble. The other Losers often used the phrase "Beep beep, Richie" whenever they needed to silence him. Although Richie misbehaved a lot in school, he received straight high marks in school besides his grades in behavior. Before Richie joined the Losers' Club, Bill noted seeing him insulting Henry Bowers and his gang, resulting in him getting chased and beaten until he cried.
Richie is known for his hobby of doing Voices and impersonations, although when he is younger most of them were awful and sounded much like himself.
Richie is shown to have had a positive upbringing. Richie's father, Wentworth, was an intelligent man with a career in dentistry who would happily indulge Richie's interest in 'voices', going so far as to use some of his sons phrases himself. Richie knew how to read his parents like 'well-worn and well-loved' books and would often engage his father in playful bartering to get extra allowance. While Richie's father did regard his son as a little silly, it's made clear that he cares about him and loves him dearly. Richie's mother, Maggie, was kind and attempted to understand her son, but struggled to. She goes so far as to wish Richie had been born a girl so she would be able to better understand some of the things he does, demonstrating her desire to be a good mother to him.
The Smoke Hole
Richie and Mike Hanlon were the only two who were able to survive Ben Hanscom's smoke hole, witnessing the coming of It to the earth thousands of years ago. Richie remembers this event twenty-seven years with great distress and pain within his eyes.
Encounter with It
Richie had his personal encounter with It after running away from Henry and the other bullies. He rested on a bench, tired from running from the group, when the Paul Bunyan statue near him came to life and began to chase and attack him. However, unlike the other Losers and their encounters with It, Richie did not believe that what he had witnessed was real. He believed it was a dream, and did not tell the others about it when they were all confessing their own encounters.
Another encounter that Richie has with It is after Bill tells the Losers what he had seen when he had opened Georgie's photo album, how it had bled and how Georgie had winked at him. Richie told Bill that he wanted to see it for himself, and reluctantly Bill agreed. Before this encounter, Richie had not taken It or even the concept of death seriously-- perhaps he had not thought about it at all. However, after stepping into Georgie's room, the reality of death hits him for the first time in his life. He begins to understand that anyone could die at any time or at any age, which causes him to panic. When he and Bill finally open the book, they witness an image of Derry many years ago, and they see boys that look identical to themselves in the picture as well. Bill accidentally touches the page and his fingers nearly go into the picture. When he pulls them out, they are covered with deep cuts. This is truly the first time Richie understands the reality of It.
Later, Richie goes with Bill into the house on Neibolt Street, the one where Eddie saw his encounter with it (the leper). In the house, he sees It take form as the Teenage Werewolf from the movie I Was a Teenage Werewolf that he had seen at the Aladdin Movie Theater days before. The Werewolf was wearing a varsity jacket with "Richie Tozier" embroidered on the chest pocket. After the werewolf gets a hold of Bill, Richie manages to wrench Bill free and throw a packet of sneezing powder at its face, which momentarily incapacitates it. It pursues them, and Bill rescues Richie in turn, pulling him out of the way before the beast can tear out his throat. They manage to get on Silver and flee, after which they collapse into each others arms and cry.
In the 2017 adaptation of It, Richie encounters it when he and the rest of the Losers Club visit the house on Neibolt street for the first time as a group. Though the entire club came, only Eddie, Bill, and Richie entered the old house. When separated from Eddie and Bill, Richie is trapped in a room full of clown figurines and statues. Sounds like absolute hell to me! When he approaches the coffin at the center of the clown-infested room, it suddenly springs open to reveal Pennywise who exclaims, "Beep beep, Richie!" Richie is frozen in utter shock, staring up at the clown with wide eyes.
As an adult, he is a famous radio DJ, going by Rich "Records" Tozier living in Beverly Hills. Richie had several failed relationships with women, but had never gotten married. The voices that he constantly practiced as a kid improved greatly and became highly revered and loved, making a lot of money off the notoriety of his comedic voices. He began wearing contact lenses as an adult as well.
Along with the other Losers, he returns to Derry after receiving a phone call from Mike Hanlon alerting him that It had returned. They all go into the sewers and Bill performs the Ritual of Chud as he did as a kid, to put a stop to It once and for all. When Bill's grip on It falters, Richie risks his life to enter the macroverse with Bill and tears him free of It's grip. They end up striking the final blow against It together, after which Richie is knocked out and Bill weeps over his inert body, convinced that Richie is dead. It is only after carrying Richie to the others that Richie regains consciousness and assures them that he is alright.
Before the final fight, Eddie loses his arm and dies. Richie has the most difficult time dealing with Eddie's death since they were close. Richie is the last person Eddie talks to before dying, stroking Richie's face with his hand and telling him, for the last time, not to call him "Eds" as he always had. At first, both Beverly and Richie refuse to leave his body in the sewers, insisting it was too dark and Eddie would not want to stay down there. After Bill assures him that it was where Eddie was 'supposed to be', he kisses Eddie on the cheek before leaving.
After these events, Richie remains in Derry with Bill and Mike for a few days before flying back to California, where he steadily starts for forget the Losers and what they had accomplished.
Appearance in 11/22/60
Richie briefly appears in the novel 11/22/60 as well, when the main character Jake Epping arrives in Derry and sees him dancing with Beverly. Jake (using the alias George Amberson) asks the two if they know about the Dunning children. He notices the special relationship they have: not romantic, but that of two friends that had gone through a lot together. He notes they were the only thing that felt good about Derry, and helps them practice dancing.
- "I didn't hear that! I didn't!"
- "Richie Tozier's the name, and doing voices is my game."
- "This here is Stan the Man Uris, he's a Jew, which means he's very smart, and says "Oi" alot!"
- ―Richie on Stanley.
- "Help! Down in the basement! There's a werewolf."
- "Oh, come on! Not the Paramount, you slimeballs! Where are the people of this city supposed to get their culture?!"
- "[In his Pancho Vanilla voice] Doesn't smell like caca to me, señor!"
- ―Richie to Eddie
- "Go blow your dad, you mullet-wearing asshole!"
- ―Richie to Henry after winning the rock fight.
- "What the hell's gray water?"
- ―Richie to Eddie.
- "Do only virgins see this stuff? is that why i’m not seeing this shit?"
- ―Richie to the Losers'.
- "News flash, Ben, School's Out for Summer."
- ―Richie to Ben.
- ―Richie reveal his phobia to the Losers.