The story traces the life of David Copperfield from childhood to maturity. David was born in Blunderstone, Suffolk, near Great Yarmouth, Norfolk, England, in 1820, six months after the death of his father. David spends his early years in relative happiness with his loving but frail mother and their kindly housekeeper, Peggotty. When he is seven years old his mother marries Edward Murdstone. David is given good reason to dislike his stepfather and has similar feelings for Murdstone's sister Jane, who moves into the house soon afterwards. Murdstone attempts to thrash David for falling behind in his studies. David bites him and soon afterwards is sent away to a boarding school, Salem House, with a ruthless headmaster, Mr. Creakle. There he befriends James Steerforth and Tommy Traddles.
David returns home for the holidays only to learn that his mother has given birth to a baby boy. Shortly after David returns to Salem House, his mother and her baby die, and David returns home immediately. Peggotty marries a man named Mr Barkis. Murdstone sends David to work for a wine merchant in London – a business of which Murdstone is a joint owner. Copperfield's landlord, Wilkins Micawber, is sent to debtors' prison (the King's Bench Prison) and remains there for several months before being released and moving to Plymouth. No one remains to care for David in London, so he decides to run away.
He walks from London to Dover, where he finds his only relative, his unmarried, eccentric great-aunt Betsey Trotwood. She agrees to raise him, despite Murdstone's attempt to regain custody of David. David's great-aunt renames him "Trotwood Copperfield" and addresses him as "Trot", and it becomes one of several names to which David answers in the course of the novel.
As David grows to adulthood, a variety of characters enter, leave, and re-enter his life. These include Peggotty and her family, including her orphaned niece "Little Em'ly", who moves in with them and charms the young David. David's romantic but self-serving school friend, Steerforth, seduces and dishonours Emily, precipitating the novel's greatest tragedy, and Agnes Wickfield, the daughter of David's landlord, becomes his confidante. The novel's two most familiar characters are David's sometime mentor, the debt-ridden Micawber, and the devious and fraudulent clerk, Uriah Heep, whose misdeeds are eventually revealed with Micawber's assistance. Micawber is painted sympathetically even as the narrator deplores his financial ineptitude. Micawber, like Dickens's own father, is briefly imprisoned for insolvency.
The major characters eventually get some measure of what they deserve, and few narrative threads are left hanging. Peggotty's brother Dan takes Emily to a new life in Australia, accompanied by the widowed Mrs. Gummidge and the Micawbers. All eventually find security and happiness in their adopted country. David marries the beautiful but naïve Dora Spenlow, who dies after failing to recover from a miscarriage early in their marriage. David then searches his soul and marries the sensible Agnes, who had always loved him and with whom he finds true happiness. David and Agnes then have at least four children, including a daughter named after his great-aunt Betsey Trotwood.