Jango Fett is a human bounty hunter, played by Temuera Morrison in Attack of the Clones (2002). StarWars.com's databank puts it plainly: in the final years of the Republic he "was regarded as the best bounty hunter in the galaxy", working out of a battered starship called Slave I and an armoured suit built around retractable wrist blades, a snare, twin blaster pistols and a jetpack with a rocket in it.
The man who is also the army
His importance to the saga has almost nothing to do with his marksmanship and everything to do with his genome. Jango is the genetic template for the Republic's clone army, grown on Kamino on a commission whose true origin the Jedi never manage to trace. Every clone trooper in three films and seven seasons of television wears his face. So does the Empire's first generation of stormtroopers.
His price
He takes payment for the template in credits and in one unaltered clone, raised as his son — Boba Fett. That transaction is the whole character in miniature: a professional who prices everything, including fatherhood, and who is not being ironic about it. Canon later adds a second unaltered clone from the same arrangement, the girl Omega, in The Bad Batch.
Mandalore, and the argument about it
Jango's relationship to Mandalorian culture is the most contested thing about him. The Legends comic Jango Fett: Open Seasons (Dark Horse, 2002) makes him a foundling adopted by the Mandalorian Jaster Mereel and a survivor of a war against Tor Vizsla's Death Watch. Current canon keeps the Concord Dawn origin and the armour but has been deliberately vague about the rest — The Clone Wars has Mandalorians dismiss him as a common bounty hunter who merely acquired the armour, which is a pointed thing for the show to put in a Mandalorian's mouth.
He dies badly, on purpose
At Geonosis, Mace Windu decapitates him in the arena in front of his son. It is a fast, unglamorous, almost throwaway death for the galaxy's best, and it is the engine for everything Boba becomes. The helmet Boba wears through four decades of subsequent storytelling is the one that rolled across the sand.
Where to read him
The Attack of the Clones novelisation gives him rather more interiority than the film has room for. In comics, Marvel returned to him with a 2024 Jango Fett miniseries written by Ethan Sacks, while Dark Horse's Open Seasons remains the definitive Legends account of where the armour came from.