He is the king of the jungle who was originally mean to his subjects, but eventually became a kind ruler.
He was voiced by Garry Chalk (who also voiced Blitzen).
It is stated that Leo was mean to all the animals in the jungle like no other lion could. He later frees a lion cub whom he calls Tooey who was captured in a net. Leo is able to free him with his claws.
He later then tells Tooey to be brave and teaches him what a lion could by looking at the astrology (Leo the Lion) to have courage. Later, Leo and Tooey try to get the other animals in the jungle to help them rescue the mother of Tooey has been captured to be sold for a circus. However the animals refuse as Leo is not kind to them.
After being lectured by Tooey, Leo is able to apologise to his subjects for his treatment of them by singing "I'm a Really Nice Guy". After that, Leo convinces them to head to the camp to free the imprisoned animals. After the plan worked, the animals cheered for Leo for being a helper.
Years later, Leo is now married to Tooey's mother with a now older Tooey being renamed Leo II.