The film does not share the book's title at Irving's request; he did not believe that his novel could successfully be made into a film. The name "Simon Birch" was suggested by him to replace that of Owen Meany. The opening credits of the film state that it was "suggested by" Irving's novel. The main plot centers on 12-year-old Joe Wenteworth and his best friend Simon Birch, who was born with dwarfism.
The story begins being narrated by an adult Joe visiting the grave of Simon Birch, the rest of the movie takes place in 1964. Simon was the smallest birth in the history of Gravestown. Nobody believed that he would survive, but Simon believed he was a legitimate miracle. Simon loved baseball despite the fact that he almost never got to play, and when he did it was only to get a walk from his small strike zone. Joe's mother, Rebecca Wentworth, got pregnant in high school, the only fact anyone knows about Joe's parentage, is that Rebecca met him on a train. The fact that she refused to reveal the identity of the father has caused Joe to be a living town scandal. Simon is also obsessed with how long he can hold his breath underwater, always trying to improve this ability.
One day Rebecca invites a man she met on the train to dinner. Ben Goodrich, a drama teacher, meets Joe and Simon and brings a stuffed armadillo for Joe. Simon doesn't believe that the niceties of church are necessary. He says, in front of the congregation, that if God had made these things a priority, they were in trouble. The Sunday School teacher belittles him stating that he doesn't belong in church, and his belief that God has a special plan for him is ridiculous.
One day, while playing baseball, Simon Birch is given the perfect pitch, and hits it. It's a foul ball that hits Rebecca in the head, immediately killing her. Simon gives Joe his most prized possession, his baseball cards as an apology. Simon and Joe have an argument Simon claiming that everything he does is ordained. Joe disagrees saying that his mother's death was an accident. Joe's grandmother informs him that there must be a plan should she die as Rebecca never told ANYONE who Joe's father was, even in confidence. Joe decides his only hope is to find his real father.
Joe and Simon believe that Joe's father may have taken the baseball. They break into the gym teacher's office to find if he has the baseball that killed Rebecca, as that would implicate him as Joe's father. It isn't there, and Joe vandalizes the office, believing that he will never find his real father. The police chief agrees to let them off, if they go to the children's retreat over their winter break. Ben picks them up from the police station and takes them for ice cream. Simon informs Ben of his destiny to be a hero, but admits that he doesn't know what that will imply. However, he fears that it could happen at any time, and he could miss it.
As the Christmas pageant arrives the children are chosen for their parts. The prettiest girl, Margerie, is chosen to play Mary; Howard is playing the angel despite his crippling fear of heights; and Simon is the baby Jesus, as he is the only one who fits in the manger. Simon agrees when he realizes that he will be able to stay next to Margerie for the entire play. Simon helps a kid not be afraid, and mentions that children listen to him because of how he looks. However the play is mostly a disaster. The turtle doves look like winged mutant turtles, the wise men cannot remember the words to "We, Three Kings", and Howard is so scared he forgets his lines. But when Simon assaults Margerie, after seeing her cleavage, she hits Joe, knocking the wind out of him, and Howard pukes on the stage.
As a result of the pageant, Simon is not allowed on the retreat and his baseball cards are taken away. However, he breaks into the reverend's office to get them back, inadvertently finding the fateful baseball implicating the reverend as Joe's father. Simon has Ben drive him to the retreat to inform Joe. Reverend Russell admits this to Joe at the retreat, just as Simon arrives with the baseball.
While Simon and Joe are riding the bus home, it crashes into a lake. When the bus driver abandons the children, and the reverend is knocked unconscious, Simon takes command to get everyone out safely. With the help of Joe, he is successful getting everyone out of the bus, but Simon nearly drowns saving the last child. Joe wakes up in the hospital and visits Simon who is dying. Simon mentions that the children listened to him because of how he looks, that the window he escaped through was "just his size" and that he held his breath for "200 Mississippi", then dies. Joe remarks that he will always remember Simon for the hero that he was.
Joe's grandmother died that summer, and he was adopted by Ben Goodrich just before his 15th birthday. The film then transitions to the present day with adult Joe at Simon Birch's grave. Joe's son Simon reminds him he has a soccer game, and they drive away.
- Ian Michael Smith as Simon Birch: This was Smith's first role in film, and he has not done film acting since. He was chosen because of his small height, due to Morquio syndrome. His role in this film was suggested by a hospital worker in Chicago. After his parents read through the novel (A Prayer for Owen Meany) they agreed to let him work on the film.
- Joseph Mazzello as Joe Wenteworth
- Jim Carrey as Adult Joe Wenteworth / Narrator
- Ashley Judd as Rebecca Wenteworth; Sandra Bullock was originally cast for the role Ashley Judd was given.
- Oliver Platt as Ben Goodrich
- David Strathairn as Reverend Russell
- Dana Ivey as Grandmother Wenteworth
- Beatrice Winde as Hilde Grove
- Jan Hooks as Miss Agnes Leavey
- Cecilley Carroll as Marjorie
- Sumela-Rose Keramidopulos as Ann
- Sam Morton as Stuart
- John Mazzello as Simon Wenteworth
- Holly Dennison as Mrs. Birch
- Peter MacNeill as Mr. Birch
- Thomas J. Burns as Simon Birch Stunt Double
The bus crash scene was filmed near Ontario's French River. The film's quarry scenes were shot at Elora, Ontario. The church featured in many parts of the film is in Lunenburg, Nova Scotia. Its black borders were painted white for the film. At the end of the film when it switches to the future, the borders are black. The baseball scene as well as many indoor scenes were filmed in Glen Williams, Ontario.
Simon Birch features R&B songs from the 1950 and 1960s, as well as four score cues by Marc Shaiman. The film's original motion picture soundtrack was released on compact disc, LP and audio cassette on September 1, 1998 through Sony Wonder, Hollywood Records and Epic Records featuring the following songs:
- "You Were There" – Babyface
- "Bread and Butter" – The Newbeats
- "A Walkin' Miracle" – The Essex
- "Mickey's Monkey" – Smokey Robinson / The Miracles
- "Can I Get a Witness" – Marvin Gaye
- "Fever" – Peggy Lee
- "Up on the Roof" – The Drifters
- "Papa's Got a Brand New Bag (Part 1)" – James Brown
- "The Nitty Gritty" – Shirley Ellis
- "Nowhere to Run" – Martha and the Vandellas
- "It's All Right" – The Impressions
- "(Your Love Keeps Lifting Me) Higher and Higher" – Jackie Wilson
- "Simon's Theme" – Marc Shaiman
- "Friends Forever" – Marc Shaiman
- "Simon's Birth" – Marc Shaiman
- "Life Goes On" – Marc Shaiman
Simon Birch holds a 44% rating on Rotten Tomatoes, with the site's consensus calling the film "Overly mushy; tries too hard to pull at the heart-strings." On Metacritic, the film has a 39/100 rating, indicating "generally unfavorable reviews." Movie critic Gene Siskel rated it the 7th best movie of 1998.
The film opened at #5 at the North American box office making $3,321,370 in its opening weekend, in fifth place. The film would go on to gross $18,253,415 domestically, against a $20 million budget, resulting as a box office bomb.