Stanley Shunpike is a minor recurring character in the Harry Potter franchise. He is a British wizard and conductor of the Knight Bus, appearing in the third, fourth, fifth and seventh books (the latter of which saw him take on the role of minor antagonist). He was portrayed by Lee Ingleby in the film adaptation of Harry Potter and the Prisoner of Azkaban and did not appear in any other films.
The Prisoner of Azkaban
Stan Shunpike was the conductor of the Knight Bus, which picked up Harry Potter after his escape from 4 Privet Drive. Despite Harry's celebrity status, Shunpike didn't recognise him and believed him to be Neville Longbottom (another wizard whose name Harry used as an alias). He was shocked when Harry used Lord Voldemort's name and was still unaware of Harry's true identity even after having it confirmed by Cornelius Fudge. He dropped Harry off at the Leaky Cauldron.
The Goblet of Fire
Stan attended the 1996 Quidditch World Cup, claiming to be the next Minister of Magic in an effort to impress a group of Veela.
The Order of the Phoenix
Stan once again appeared as the conductor of the Knight Bus, where he met Harry again and recognised him. He transported Harry and his friends to Hogwarts School of Witchcraft and Wizardry. During the trip, the Auror Nymphadora Tonks threatened to curse Stan if he said Harry's name, as he had already been the victim of one assassination attempt from Dementors that year.
The Half-Blood Prince
While Stan did not appear in the sixth book, it is mentioned in the Daily Prophet that he was arrested and sent to Azkaban for trying to impress his friends by claiming to have inside knowledge of the Death Eaters. While he was found to have no knowledge of the Death Eaters, he was still imprisoned as the Ministry needed to keep up a façade of progress.
The Deathly Hallows
During the Death Eater takeover, Stan was broken out of Azkaban along with Bellatrix Lestrange and Lucius Malfoy and placed under the Imperius Curse, forcing him to join the Death Eaters. He took part in the Battle of the Seven Potters, pursuing Harry and Hogwarts groundskeeper Rubeus Hagrid on a broomstick. Once again, Stan did not know for sure that it was Harry (as he had been given decoys to distract his pursuers), however this soon changed when Harry used a spell to knock Stan's hood off, revealing his face. Knowing that Stan was not a real Death Eater, and that using the Stunning Spell on him would cause him to fall to his death, Harry instead disarmed him using the Disarming Spell. This caused the other Death Eaters to recognize Harry and attack him.
It is unknown if Stan participated in the Battle of Hogwarts, however it is likely that after the battle and Voldemort's death he was freed from the Imperius Curse and given a full pardon.