Flower, 26, has already been handed a six month ban from playing by the RFL, and received further punishment following Wigan’s own disciplinary process.
He was found guilty of gross misconduct due to violent conduct, bringing into disrepute the Wigan club and the game of rugby league.
Three months of the fine will be suspended, and the Wales international must also undergo a rehabilitation programme involving service with young people in the community.
Warriors chairman Ian Lenagan said: “The Wigan Club has followed RFL protocol fully in conducting internal disciplinary action with Ben Flower following the incident at the Grand Final.
“We were extremely disappointed and angry at the actions of Ben Flower and stand in agreement with the Rugby Football League and the six month ban from playing which they handed down to Ben last month.
“There is no doubt that the reputation of this great Club has been damaged by this incident.
“This significant fine combined with the requirement for community service has been imposed to affirm Wigan’s position that this is not the type of behaviour we want or expect from any of our players.
“Ben’s action was totally unacceptable in Rugby League but was out of character and one for which he is deeply remorseful. It is our judgement that we should not dismiss him but should punish him financially and then support him through what will be a difficult rehabilitation period and a difficult return to playing.”
He will be on the sidelines until April, and will miss 10 Super League matches and the World Club Series fixture against Brisbane.
Flower said: “I fully accept this decision taken by Wigan. I deeply regret my actions and I am grateful for the support that my club has given me throughout this process.
“It is a relief to reach closure on the incident and I hope to move forward now and rebuild the trust of my club, team-mates and the Wigan fans.”