The 322nd was a group of clone cadets that belonged to the Clone Youth Brigade of the Galactic Republic during the time of the Clone Wars. During 21 BBY, Boba Fett managed to get inside the Clone Youth Brigade, and when questioned by another clone cadet, Whiplash, he claimed that he had been moved from the 322nd. Fett's infiltration allowed him to sabotage the _Venator_-class Star Destroyer called Endurance, as part of a plot to assassinate Jedi Master Mace Windu in revenge for the death of his father, Jango Fett.
The initial reference to the 322nd occurred in "Death Trap," which is the twentieth episode from season two of the Star Wars: The Clone Wars television show, which came out in 2010.