There were three successive heads of the Wizengamot who possessed chestnut and unicorn wands, the combination, as Garrick Ollivander noted, showing a predilection for those concerned with matters of justice and law.
Albus Dumbledore held this title for several years, until 1995; a discrediting campaign that the Ministry of Magic and the Daily Prophet carried out that year caused him to lose the position. Dumbledore was reinstated when the Ministry was forced to acknowledge Lord Voldemort's return to power, and presumably held the title until his death.
Given that the Wizengamot was presided over by the Minister for Magic in the 1995 trial of Harry Potter, the period in which Dumbledore had lost this title, it is unclear whether the Minister always heads the Wizengamot, or if he took on the role of Chief Warlock himself. It is also possible that the Chief Warlock acts as an impartial executive figure, much like the Queen of England does over British and Commonwealth Parliaments.
In his obituary for Dumbledore, Elphias Doge praised the wisdom the late Chief Warlock had displayed in several judgments while he had occupied that position.
In 1544, Jarleth Hobart invited the Chief Warlock of the Wizengamot to witness his demonstration of the Levitation Charm, but the demonstration was a failure because he was attempting flight, but the Levitation Charm was not a flight spell. Once Hobart realised the true nature of the Levitation Charm, he scheduled another demonstration, which went a lot better until as a grand finale he levitated off the Chief Warlock's hat, only for it to be revealed the Chief Warlock was also wearing a wig. Hobart survived the subsequent duel only by levitating the Chief's robes over his head and then making a break for it.
- Harry Potter and the Philosopher's Stone (First appearance)
- Harry Potter and the Order of the Phoenix
- Harry Potter and the Deathly Hallows (Mentioned only)
- Wonderbook: Book of Spells