Defense Against the Dark Arts is a subject taught at Hogwarts School of Witchcraft and Wizardry. Since the time that Tom Riddle. asked again for the Defense Against the Dark Arts , the position has been seen as cursed, as no one can keep up with the job for more than a year. After Voldemort's first reign of power Snape wanted the position, but it might have been thought a bad idea as he was one of Voldemort's most trusted Death Eaters at the time, and Dumbledore might not have wanted Snape's bad side to be bought out. Since Harry started the school Dark Arts teachers have changed each year. In Defense Against the Dark Arts, you are taught many spells which help duels, or other needs, such as Boggarts.
 First Year
He was a teacher that was used as a host for Voldemort, during his time he was shown to be very timid, different to any of the other teachers. During his year he attempted to get the Philosopher's Stone, but failed due to Harry figuring out his plan. He finished his teaching at Hogwarts when Harry Potter killed him due to his connection with Voldemort.
 Second Year
He was chosen as he had books talking about all his adventures with many different magical beings. This turned out to be a lie, and he was just really good at using Memory charms, one of which backfired when he tried to use Ron's wand against him causing him to lose his memory while he was taken to the Chamber of Secrets. During his lessons he tried showing Cornish Pixies, during the lesson he let them out and they went out of control, he then left Harry, Hermione and Ron to sort it out, and since then he focused on reenactments from his books.
 Third Year
From the start he knew his job wasn't going to be permanent as he was a werewolf, and he didn't feel that parents are going to want a werewolf dealing with their children. During his year he took many days off to retreat to his office to transform into his werewolf form without causing damage. So at the end of the year, before news that he was a werewolf was bought out he decided to resign, saving the school from having to fire him. During this year Defense Against the Dark Arts was more of a practical lesson, with them acting out the skills rather than just learning them.
 Fourth Year
This teacher was an Auror previously, and was asked by Dumbledore to be a teacher before Death Eaters appeared at the Quidditch World Cup. During the year, he did what no other teacher had done and showed them the Unforgivable Curses. Later that year it was found out that the real Alastor Moody had been locked in a trunk, and duplicated using a Polyjuice potion. At the end of the year he didn't want to return the following year. This year the class was shown how the unforgivable curses work using a spider.
 Fifth Year
She was appointed by the Minister, as teachers kept leaving after one year, and applied a strict study of theory only. This wasn't liked by students, so they created a group, which was later found by Umbridge, as she moved from Dark Arts teacher to Head teacher. This lesson had no practicality during this year, as it was not believed that the Dark Lord had returned.
 Sixth Year
He finally got his dream job in the sixth year Harry Potter stayed at the school. His job as Potions master was taken by Professor Slughorn, and Snape taught Defense Against the Dark Arts. At the end of the year, Snape killed Dumbledore, and ran away from the school, later to return as Headmaster.
 Seventh Year
This teacher changed it from being Defense Against the Dark Arts to teaching Dark Arts, his term of teaching ended when he was arrested after Voldemort's fall.
The teachers are unknown from when Harry left the school, but it was mentioned that Harry returned as a guest teacher sometimes after the Battle of Hogwarts. The post was filled permanently and this was revealed by J.K Rowling, that the curse had been lifted.