Simon's latest infraction was stepping on Pittsburgh's Jarkko Ruutu with his skate during a game last weekend.
"Several factors were considered in imposing the longest suspension in NHL history for an on-ice incident," league disciplinarian Colin Campbell said. "While it was fortunate there was no serious injury to Mr. Ruutu as a result of Simon's action, the deliberate act of kicking an opponent with an exposed skate blade, especially where the opponent is in a vulnerable position, is and always has been a repugnant and totally unacceptable act in the game of hockey."
Simon missed the first five games of this season while completing a 25-game ban handed out in March. That was the previous record for an NHL suspension. This is the seventh time in Simon's career that he has been suspended.
The 35-year-old player went on a leave of absence Monday to receive counseling, and then met with Campbell on Tuesday.
Simon agreed he needed time away from hockey after he stomped on Ruutu during a 3-2 loss to the Penguins on Saturday. Simon drew a match penalty when he pulled out Ruutu's leg with his, sending the forward to his knees between the team benches. He then stepped on the back of Ruutu's leg with his skate, and was ejected.
On March 11, Simon was suspended 25 games - 15 regular-season games, five playoff games, and five games to open this season - for his two-handed stick attack to the face of New York Rangers forward Ryan Hollweg.
"While the act itself was extremely dangerous, the fact that this is the eighth incident requiring the imposition of supplementary discipline on Simon compelled me to impose a very severe penalty in this case," Campbell said. "This response serves not only the purpose of imposing appropriate punishment for the player involved, but also the purpose of deterring the player and all other players from engaging in similar conduct in the future - hopefully creating a safer long-term work environment for all NHL players."
Simon met with Islanders owner Charles Wang, general manager Garth Snow and coach Ted Nolan during practice Monday and they agreed he should seek help.
He was to be paid during his time away from the club, but now with the suspension, Simon will forfeit $292,683.
"It's excessive," Nolan said Wednesday after the Islanders skated before that night's game against the Buffalo Sabres. "What I think has no bearing on the facts. The league suspended him ... now we have to support Chris while he goes through this process and give him all the compassion and all the support we can give him as an organization."