Cedric Diggory is a Hufflepuff student two years above Harry. In addition to being a Hufflepuff prefect, he is the house Quidditch captain and Seeker. His father is Amos Diggory, who works at the Ministry of Magic. Cedric is first mentioned in Harry Potter and the Prisoner of Azkaban when the female Gryffindor Chasers say that they find him "strong and silent" amid giggles prior to the Hufflepuff-Gryffindor match, and shows a notable streak of modesty and fairness; when he catches the Snitch and wins the match after Harry falls off his broomstick following an encounter with the Dementors, he finds the match to be unfair and protests that the result should be nullified and the match replayed. He is described as being exceptionally handsome, with a straight nose, dark hair, and grey eyes.
In Harry Potter and the Goblet of Fire, Cedric is selected as the Hogwarts champion for the Triwizard Tournament. After Harry is also picked to compete, Malfoy makes "Support Cedric Diggory/Potter Stinks" badges, which Cedric tries to discourage his housemates from wearing. For the first task, Cedric transfigures a rock into a dog in order to distract his dragon and successfully finds his golden egg, but he receives a burn on his cheek in the process. He is later Cho Chang's date for the Yule Ball. As compensation for Harry's warning about the dragons before the first task, Cedric assists Harry in solving the clue of the second task by telling him to take a bath with the egg in the prefects' bathroom, and just "mull things over in the hot water". Cedric is the second of the four champions to find the village of the merpeople and rescue his hostage, using a Bubble-Head Charm, but surfaced one minute over the one-hour time limit.
During the third task, Harry saves Cedric's life twice while in the maze, and when they find the Triwizard Cup, Cedric refuses to take it without Harry, so they grab hold of it together. The cup turns out to be a Portkey which transports them to the Little Hangleton graveyard, where Voldemort and Peter Pettigrew await Harry's arrival; Pettigrew murders Cedric on the spot upon Voldemort's order to "kill the spare". Before Cedric Diggory's death he claims to have "so many regrets", and then he died. In the midst of the Priori Incantatem effect during Harry's duel with Voldemort, Cedric's spirit appears and asks Harry to take his body back to his parents . Despite an attempted cover-up of the incident by the Ministry of Magic, Dumbledore candidly reveals the true nature of Cedric's demise to the students at the end-of-term feast, stating that to attribute it to an accident would be "an insult to his memory". Cedric Diggory was in his sixth year at Hogwarts in The Goblet of Fire.
Robert Pattinson appeared as Cedric in the film adaptation of Harry Potter and the Goblet of Fire, and made a brief cameo in Harry Potter and the Order of the Phoenix in a flashback taken from Goblet of Fire.