Kalo was an Iotian mobster employed by boss Bela Okmyx. Kalo captured Captain James T. Kirk, Doctor Leonard McCoy, and Mr. Spock as they beamed to the Northside Territory on Sigma Iotia II, a planet whose society was based on Earth's gangster period. Kirk would later distract Kalo with a game of fizzbin to make an escape. (TOS: "A Piece of the Action")

Kalo was played by actor Lee Delano.