What is the name of the hyena leader?

The hyena leader in The Lion King is Shenzi.

Shenzi is the female spotted hyena who leads the trio serving Scar in the 1994 animated film. Her companions are Banzai and Ed, and the three live in the Elephant Graveyard. Scar recruits them by promising access to food and influence after he takes the throne.

The hyenas help Scar arrange the wildebeest stampede that kills Mufasa and later pursue Simba. Shenzi is often confused with Zira, but Zira is a lioness introduced in The Lion King II: Simba's Pride. Banzai and Ed are Shenzi's fellow hyenas, not alternate names for the leader.

Whoopi Goldberg voiced Shenzi in the original animated film. Florence Kasumba voiced her in the 2019 remake, where Shenzi is also portrayed as the leader of a larger hyena clan.