King Daphnes Nohansen Hyrule is the last king of Hyrule. To meet with Link, he remotely operates the King of Red Lions, a talking boat, using magic. By the end of the game, the King wishes to the Triforce for Hyrule to be destroyed and stays with the kingdom as it is flooded.
Other Kings of Hyrule appear or are mentioned in the series. In A Link to the Past, the king only appears during the intro and ending credits. In Ocarina of Time, it is stated that Princess Zelda's father is the king and Ganondorf is seen approaching and kneeling to him when Link and Princess Zelda first meet, although the king himself is never shown and his ultimate fate is never revealed.
Source: Wikipedia, "Characters in The Legend of Zelda series," available under the CC-BY-SA License.