The story, set in post war New Orleans, begins with the birth of the protagonist whose character was played by Brad Pitt and his name is Benjamin. Benjamin was born with a rare condition. He was born with the physical appearance of a 70 year old man and he could already speak. After discovering what his newborn son looked like coupled with the death of his wife mere hours after giving birth,the father, Mr Thomas Button decided to get rid of Benjamin because he was embarrassed. He takes the baby away and left it at the porch of a nursing home.
A couple working at the nursing home named Queenie Tizzie found the baby Queenie decided to keep it much to Tizzie's objection. Benjamin lives in the nursing home and sleeps with his adopted mother in her room along with the rest of the residents there who come and go while he keeps on growing younger.
One day, Benjamin met Daisy Fanning whose grandmother is a resident at the nursing home and begins a humble friendship with the then girl. Daisy visits her grandmother and maintains her friendship and adventures with Benjamin much to her grandmother's disapproval. Benjamin continues to grow younger and took up a position as a sailor in a tugboat , left his house, travelled as far as Russia on his boat and even surviving a war. During his journeys there, he was exposed to brothels and bars where he met a certain Thomas Button ( his father) but the man did not reveal who he was.
In the meantime, Daisy Fanning was growing to be a beautiful woman and a graceful ballerina. Benjamin learns of this the two met from time to time when she was visiting her grandmother in the nursing home. Daisy even tried to seduce Benjamin but he refused. When Benjamin came to see one of Daisy's performances in New York, he learns that she is seeing another dancer.One day, she met with a car accident one day after rehersals and broke her leg, forever erasing her possibilities of ever dancing again. Benjamin visited her at the hospital only to be told to never come back to see her.
In 1962, Benjamin returned home and met Daisy. They fell in love while their ages met in the middle, both comfortably in their thirties.They got married and moved in together. Daisy opened up her own dance studio, teaching young children ballet. A few years later they had a daughter called Caroline. Benjamin realised that he could not possibly be a father to Caroline due to reverse aging and decided to leave his assets and possession behind for when Caroline turns 1.
In 1980, Benjamin came back only to find out that Daisy has married another man.Caroline only got to know that Benjamin was her real father towards the end of the story while reading Benjamin's diary to her dying mother on her deathbed.
The getting-younger Benjamin then left and travelled the world. He became younger thru time and was found at the nursing house where he once grew "up" in as a young boy who is confused with characteristics of dementia. Daisy moved into the nursing home and decided to take care of Benjamin. Benjamin finally died in her arms as a baby in 2003.