The story follows 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. During the marriage, partly to get him out of the way and partly because he strongly objects to the whole proceeding, David is sent to lodge with Pegotty’s family, in Yarmouth. Her brother, the fisherman Pegotty, lives in a houseboat with his adopted relatives Em’ly and Ham, and an elderly widow, Mrs Gummidge. Little Em’ly is somewhat spoilt by her fond foster father, and David is in love with her. On his return, 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. Between them they tyrannise over his poor mother, making her and David’s’ lives miserable, and when in consequence David falls behind in his studies, Murdstone attempts to thrash him – partly to further pain his mother. David bites him and soon afterwards is sent away to a boarding school, Salem House, under a ruthless headmaster, Mr. Creakle. There he befriends an older boy, James Steerforth, and Tommy Traddles. He develops an impassioned admiration for Steerforth, perceiving him as something noble, who could do great things if he would.
David goes 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 the local carrier, Mr Barkis. Murdstone sends David to work for a wine merchant in London – a business of which Murdstone is a joint owner. Copperfield's tragicomic landlord, Wilkins Micawber, is arrested for debt and sent to the King's Bench Prison, where he remains 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 had come to Blunderstone at his birth, only to depart in ire upon learning that he was not a girl. However, she takes pity on him and agrees to raise him, on condition that he always tries to ‘be as like his sister, Betsy Trotwood” as he can be, meaning that he is to endeavour to emulate the prospective namesake she was disappointed of, 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 which David is called by in the course of the novel.
David is sent to another school by his aunt, as he calls his great-aunt. This is a far better school than the last he attended, and is run by Dr Strong, whose methods inculcate honour and self-reliance in his pupils. During term, David lodges with the lawyer Mr Wickfield, and his daughter Agnes, who becomes David’s confidante. Wickfield has a secretory, the 15 year-old Uriah Heep.
By devious means Uriah Heep gradually gains a complete ascendancy over the aging Wickfield, to Agnes’ great sorrow. Heep hopes, and maliciously confides to David, that he aspires to Agnes’ hand. Ultimately with the aid of Micawber, who has been employed by Heep as a secretary, his fraudulent behaviour is revealed, and Wickfield vindicated; he had been apparently instrumental in the loss of David’s Aunt Trotwood’s fortune, which Heep had in fact stolen. At the end of the book, David meets him in a prison, for attempting to defraud the Bank of England.
David's romantic but self-serving school friend, Steerforth, seduces and dishonours Emily, offering to marry her off to one of his servants before finally deserting her. Her uncle Peggotty manages to find her with the help of London prostitute Martha, who had grown up in their county. Ham, who had been engaged to marry her before the tragedy, died in a storm off the coast in attempting to succour a ship; Steerforth was aboard the same and also died. Peggotty takes Emily to a new life in Australia, accompanied by the widowed Mrs. Gummidge and the Micawbers, where all eventually find security and happiness.
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 weds 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.