* Quirinus Quirrell
Quirrell was the Muggle Studies teacher at Hogwarts. After some time in the position, he traveled throughout Europe for a full term. After his return to the school, he was appointed as D.A.D.A. teacher, receiving little respect from students for his stuttering and jittery behavior, supposedly from encountering vampires somewhere in Romania. He was killed at the end of the year after attacking Harry, sustaining excruciating pain while supporting the fragmented soul of Lord Voldemort in his own body.
* Gilderoy Lockhart
Lockhart's tenure ended when he attempted to attack Harry Potter and Ron Weasley outside the Chamber of Secrets, and was hit by a backfiring Memory Charm from Ron's malfunctioning wand. Lockhart was admitted to St Mungo's Hospital for Magical Maladies and Injuries with amnesia. Lockhart was regarded by the students and teachers largely as a joke and the majority of the school was elated to see him go.
* Remus Lupin
Lupin resigned after being revealed as a werewolf by Severus Snape, out of fears that the parents of the students would not accept a werewolf as a Hogwarts teacher. Nevertheless, Lupin was enormously popular with the students and teachers, widely regarded as an effective, competent, and fair instructor and perhaps the best Defence Against the Dark Arts professor. Severus Snape stood in for Lupin as D.A.D.A. instructor on a monthly basis during the school year.
* Alastor Moody, a.k.a. Barty Crouch Jr
Moody, a retired Auror with the Ministry of Magic, was brought out of retirement to replace Lupin at Hogwarts, and keep a protective eye on Harry Potter. As an Auror, Moody possessed many special magical devices, including a Sneakoscope, Secrecy Sensor, Foe-Glass and other Dark detectors. He later turned out to be an impostor – Barty Crouch Jr in disguise – having abducted the real Alastor Moody shortly before the school term began, using Polyjuice Potion to take on Moody's appearance. Crouch (as Moody) was nonetheless very effective, teaching the students true defensive skills and actively demonstrating the power of the Dark Arts. After the discovery of Crouch's secret, Moody was released from captivity and returned to retirement; while Barty Crouch Jr, as an escaped prisoner from Azkaban, received the Dementor's Kiss. An interesting thing to note about Moody's period as teacher was that he briefly mentioned that he was only hired for the year anyway; whether this was truly the case or whether Crouch was lying at the time is left ambiguous.
* Dolores Umbridge
Umbridge was assigned to the position acting as an agent for the Ministry of Magic, and was later named High Inquisitor as the Ministry worked to gain control of Hogwarts. As D.A.D.A. instructor, Umbridge taught only theoretical aspects of defence and topics like conflict avoidance and fleeing, in stark contrast to practical combat and resistance teachings of the previous two D.A.D.A. instructors. During Umbridge's tenure, Harry, along with Ron and Hermione Granger, provided clandestine D.A.D.A. instruction for their fellow students, based in part on some of the experiences Harry gained in his conflicts with Voldemort and others. They formed Dumbledore's Army, a secret club dedicated to training interested students in the practical elements of wizarding combat that Umbridge refused to teach. Umbridge was known to impose harsh punishments on Harry during her term, such as writing lines in his own blood during detention, as a way of forcing Harry to renounce his belief that Voldemort had returned to power. She challenged Dumbledore for his position as Headmaster, due to his support for Harry. Umbridge was removed from Hogwarts after Voldemort and his Death Eaters attacked at the Ministry of Magic, which proved that he had returned to power; and also proved the need for practical D.A.D.A. instruction for Hogwarts students.
* Severus Snape
Snape assumed the post of D.A.D.A. instructor, unexpectedly by most of the students, and was replaced as Potions Master by Horace Slughorn. Little is said about Snape's tenure as D.A.D.A instructor other than that he seemed to focus on non-verbal spells, defence against creatures and spells used by Lord Voldemort and his Death Eaters, and was looking after Draco Malfoy, who was acting enigmatically, for much of the term. He and Malfoy fled the school after the Battle of the Astronomy Tower, during which Snape killed Albus Dumbledore. The next year when Voldemort took over the Ministry, Snape was appointed headmaster of the school.
* Amycus Carrow
In September of 1997, Carrow became the Defence Against the Dark Arts Professor at Hogwarts though it became more of a Dark Arts class. He was arrested after Voldemort fell, and it is unclear who took over after him, although it has been mentioned that Harry Potter did sometimes come to teach D.A.D.A. as a guest teacher in the years following the Battle of Hogwarts.