Matt Nickerson has been banned for 20 games after hitting a fan during MK Lightning's defeat to Guildford Flames on Sunday.
The 33-year-old American left the bench to engage in a fight with a member of the Flames team at the end of the game, abusing an official in the process.
His altercation with the referee earned him a six-game ban, but upon leaving the ice, he struck a fan on the back of the head, earning him a further 14 games.
A statement from the Elite League said: "Fighting off the ice surface does not have the same rules as fighting on the ice surface; and hitting a fan off the ice surface is treated with an entirely different level of severity.
"Nickerson left the players bench for the purpose of engaging in a physical altercation with an opposing player.
"He physically broke free of the linesman to try to engage an opposing player on multiple occasions.
"While stepping off the ice, Nickerson then delivered a forceful backhand punch directly to the head of an unsuspecting fan."