King of the Hill allows players to observe and react to the match going on between the champion and the next challenger as they wait to play the defending champion. Spectators have the option to allow their avatar to perform reactions based on the fight taking place. Kombatants earn Respect Points based upon the recently played match, with spectators given the opportunity to rate the winner of the battle 0.0 out of 10. After the ratings have been awarded, the loser leaves the stage and joins the spectators while the next challenger in line fights the defending king.
Xbox 360 owners are able to import their Xbox Live avatar directly into the mode, while PlayStation 3 owners use the default character avatars.
In between games, players are able to join King of the Hill rooms. Players are able to jump in and out of King of the Hill rooms easily, without interrupting gameplay. However, the avatar they use is not seen until the next round is over.
Both players and spectators also have the option to toggle in and out of fullscreen mode simply by pressing BACK and SELECT on the Xbox and PlayStation systems, respectively.
Spectators are capable of entering a certain input that would have their avatar react to the battle. The normal actions are: Cheer, Approve, Disgust, and Boo.
Aside from the basic four actions, there are different variations of the actions that include clapping or yelling "FIGHT!" These "Special Actions" require special button input sequences to activate, similar to special moves in-game:
- #1: Down, Up, Y / Triangle
- Curse: Up, Up, B / O
- Yell "FATALITY!": Up, Up, Right, Right, X / Square
- Yell "FIGHT!": Left, Right, X / Square
- Yell "FINISH HIM!": Left, Right, Left, Right, Y / Triangle
- Laugh: Down, Up, Down, A / X
- Say "I'm not worthy": Down, Down, Y / Triangle
- Clap: Right, Up, Y / Triangle
- Cheesy: Left, Up, Down, B / O
- Cover face: left, right, B / O
- Devil horns: Down, Up, X / Square
- Summon diamond: Up, Down, Left, Y / Triangle
- Double devil horns: Up, Down, Y / Triangle
- Summon ice: Right, Right, Right, Left, Y / Triangle
- Hop: Up, Up, X / Square
- Lighter: Down, Down, Up, Up, X / Square
- Point/look away: Right, Right, X / Square
- Raiden pose: Left, Left, Right, Right, X / Square
- Shake head: Left, Right, A / X
- Sleep: Down, Down, Down, B / O
- Stink wave: Right, Left, B / O
- Stretch: Up, Down, Down, B / O
- Throw tomato: Down, Down, Down, Up, A / X
- King of the Hill is not featured in the PlayStation Vita version of the game.
- In Mortal Kombat (2011) on the PlayStation 3, King of the Hill did not feature Kratos and Sheeva as selectable avatars.
- Characters who were DLC also do not have avatars.
- This mode was also featured in NetherRealm's next game; Injustice: Gods Among Us.