Bill works as a curse-breaker in Egypt for Gringotts Wizarding Bank. He is a tall man, with long hair that he ties in a ponytail. Harry thinks that he wouldn't look out of place at a Muggle rock concert; he wears an earring with what looks like a fang dangling from it, and dragon hide boots. He and Charlie are staying in Fred and George's bedroom during their stay at The Burrow.
Bill and Charlie have a bit of fun whilst setting up tables for dinner in the garden of The Burrow. Bill is using his wand to control one of the two tables in the air, smashing it against Charlie's table and trying to knock it out of the air. After Percy angrily asks them to keep the noise down, Bill directs his table safely on to the grass and sets it for dinner.
Ron tells Harry that Bill once had a pen-friend at a magical school in Brazil. He wanted to go on an exchange trip, but Arthur and Molly could not afford it. Bill's pen-friend was very offended, and sent Bill a cursed hat, which made his ears shrivel up.
Bill arrives at the tents just after the group has started cooking lunch, accompanied by Percy and Charlie. Bill buys a green rosette from one of the vendors at the campsite to support Ireland.
Bill travels back to The Burrow with the rest of his family the morning after the Quidditch World Cup. As his father leads Molly towards the house, after her emotional greeting in the front yard, Bill picks up Molly's discarded copy of the Daily Prophet, and brings it into the kitchen with him. He listens as the family discusses Rita Skeeter's article, and tells Percy to shut up when his brother starts to talk about his work on cauldron thickness.
On the Sunday before the students are due to return to Hogwarts Bill sits in the living room playing Wizard chess with Ron. When Molly and Percy start to argue about Rita Skeeter's article, Bill interrupts, telling them that if Arthur hadn't made any statement about the events in the woods at the World Cup, Rita would have said it was disgraceful that nobody from the Ministry had commented. He was once interviewed by Rita Skeeter through his job as a curse breaker for Gringotts, and was described as a 'long-haired pillock'.
Bill accompanies his family, Harry and Hermione to Kings Cross Station. He tells them that he almost wishes he were back at Hogwarts this year, as they are going to have a very interesting time, but won't reveal anything more.
Bill joins his mother and the families of the Triwizard champions in the chamber off the Great Hall on the morning of the third task. He, Molly and Harry spend the morning walking the castle grounds with Harry, seeing both the Beauxbatons carriage and the Durmstrang ship. The three are joined for lunch by the twins, Ginny and Hermione. After the evening feast, Bill makes his way to the Quidditch pitch to watch the third task along with the other spectators.
Bill joins his family in the hospital wing after the third task, questioning Madam Pomfrey about Harry's whereabouts. The group settle themselves in chairs on either side of Harry's bed after he arrives, quietly keeping watch over him. Later that night, after the confrontation with Cornelius Fudge, Bill offers to find his father and discreetly inform him of the events of the day, and let him know that Dumbledore will be in contact soon. He leaves the hospital wing immediately after saying goodbye to Harry and his mother.
Bill is a member of the Order of the Phoenix. He applied for a desk job in Gringotts, moving back to England from Egypt to work for the Order. The twins reveal that there have been compensations to Bill's relocation; Fleur Delacour is working at Gringotts to improve her English and Fred jokes that Bill has been giving Fleur a lot of private lessons.