Vernon Dursley is Harry’s uncle. Vernon is a large, beefy man with a moustache and very little neck. He is the director of a firm called Grunnings, which manufactures drills. Vernon and his wife Petunia took Harry into their home after he was orphaned. Vernon often threatens and bullies Harry and, like Petunia, deeply resents his nephew's presence. He despises anything out of the ordinary and refuses to hear anything to do with the magical world.
After his business deal has been ruined, Vernon discovers that Harry is forbidden to perform magic outside of school. He locks Harry in his room, bars his windows and installs a cat-flap through which Petunia delivers his meals.
Vernon and Petunia discuss Harry as they watch the news one afternoon during the summer. They are suspicious that Harry keeps trying to watch the news. The Dursleys hear a loud cracking noise coming from the street outside their house, breaking the silence on the street like a gunshot. Vernon gives a bellowing oath when the noise occurs, and the sound of breaking china comes from the living room.
Vernon is furious when Harry is revealed to have been hiding outside number four, Privet Drive, under the living room window, and sees that Harry has his wand drawn. He grabs Harry through the open window, his hand closing tightly around his throat, and snarls at Harry to put the wand away. Vernon yelps and lets go of Harry as though he has received an electric shock as, during their struggle, some invisible force appears to surge through Harry, making him impossible to hold. Vernon attempts to divert his neighbours' attention from number four, claiming that the noisy 'crack' that began the ruckus was a car backfiring. He grins in a horrible, manic way until all the curious neighbours disappear from their various windows, and beckons Harry towards him. Vernon believes that Harry is responsible for the cracking noise that sounded outside the house, and wants to know why Harry was lurking under the window. He and Petunia are suspicious when Harry claims he was listening to the news, and don't believe their nephew, certain that 'his lot' don't make it onto the Muggle news. He and Petunia know that Harry gets his wizarding news by owl, and don't believe his claim that the owls haven't brought him anything over the summer.
Vernon agrees to sign Harry's Hogsmeade permission form on the condition that Harry keep up the pretence that he attends St Brutus’s Secure Centre for Incurably Criminal Boys, and not Hogwarts. When Marge inflates, Vernon tries to catch her and is attacked by her faithful bulldog Ripper when he does so. He bellows at Harry, demanding that he put her right, but Harry points his wand at him and storms out of the house.
Vernon waits for Harry at King's Cross station. He stands a good distance away from Mr and Mrs Weasley, and eyes them suspiciously. His worst fears seem to be confirmed when he sees them greeting Harry. Vernon greets Harry is his usual, unfriendly manner. He spots the letter Harry is holding, and tells him that he won't be signing another form if that's what it is. He looks horrified when Harry tells him about his Godfather, Sirius, and that he will be keeping in touch.
Vernon is livid when he receives a letter from Molly Weasley, with an envelope covered in stamps, especially since the postman noticed and found it odd. He is furious with Harry for mentioning the ways of the wizarding world, under his roof, and seems ready to refuse to let Harry attend the Quidditch World Cup with the Weasleys. Vernon only gives his permission after Harry mentions that he is in contact with Sirius Black, his godfather. Vernon is worried about the notorious Sirius getting the impression that Harry is being mistreated, and knows that the only way to prevent this is to let Harry go. He refuses to take Harry to the Weasleys, and insists that they collect Harry from Privet Drive themselves.
The closer it gets to 5 o'clock, the time the Weasley family are due to arrive, the more irritable Vernon becomes. He is unhappy about them coming to his house, and tells Harry he hopes they are dressed in 'normal' clothes.
Vernon wears his best suit to greet the Weasleys, in an attempt to look impressive and intimidating. He assumes the Weasleys will be driving to Privet Drive, and when 5 o'clock comes and goes, he stands waiting by the front door, peering up and down the street to watch for them. Vernon and Petunia are annoyed that the Weasleys are late, and Vernon paces up and down the living room as they wait.
He is panic-stricken when he hears voices coming from behind the fireplace at Number 4, Privet Drive. He doesn't understand what is going on, and is furious with Harry. When Mr Weasley tells Harry to stand back, Vernon advances towards the fire, wanting to know what they are going to do. He is speechless after Arthur Weasley blasts the electric fire from the wall.
Vernon ignores Harry's initial goodbye, but reluctantly replies after Arthur prompts him, very aware that the wizard is holding a wand. He panics when, after eating one of the sweets dropped by Fred, Dudley's tongue swells and grows to over a foot long. He completely loses control, and starts to throw china ornaments at Arthur, refusing to let the wizard near his son. Dudley's tongue reaches four foot in length before Vernon and Petunia finally allow Arthur to shrink it.