Origin
Before the zombies came, Ezekiel was zookeeper caring for the tiger, Shiva. At the outbreak, Ezekiel returned to the zoo and saw Shiva alone and famished. He released her and took her with him. When word spread that there was a man with a tiger in the area, people told each other wild tales about how the tiger was found in the wild and that the man had wrestled it down and put into submission. When those people came to him, Ezekiel remembered his community theatre training and took on the persona of King Ezekiel, and formed The Kingdom.
Creation
Ezekial was created by Walking Dead writer Robert Kirkman and artist Charlie Adlard.
The Walking Dead
Ezekiel is approached by Paul Monroe and Rick Grimes to go to war against The Saviors, which he agrees to. He invites Team Grimes to The Kingdom in order to plan their attack on The Saviors, and becomes friendly with Michonne, explaining to her how he came to be in charge of his group.