The 23-year-old has been handed a one-week suspension for his illegal cleanout of England full-back Mike Brown in the Wallabies' 33-13 victory at Twickenham.
Hooper pleaded guilty to the offence which carries a minimum two-match penalty.
But independent judicial officer Alan Hudson took Hooper's contrition and clean record into account, reducing the penalty to one game.
"I was a bit shocked to find out I was being cited from the weekend," Hooper said.
"However I think I had a fair trial and can move on and help the team be in the best position for this weekend and train with them.
"I'll be focusing more on day to day and focusing on what will be the team running out this weekend, which is a big match against Wales at Twickenham
"Personally you want to play in every Test match that you can.
"So, straight away it's a huge disappointment that I can't be involved and put myself forward for selection.
"And secondly to be a part of a team in a World Cup and not be there is again another blow."
Hooper's absence is a blow to the Wallabies, who are also likely to be without injured duo Israel Folau and Rob Horne for the Wales clash.
Coach Michael Cheika must now decide whether to shift David Pocock to openside flanker and start Ben McCalman at number eight, or unleash young gun Sean McMahon at number seven.
"Both are outstanding players and are in really good form," Hooper said of McCalman and McMahon.
"Whoever it is is going to do a fantastic job."
Cheika will name his team on Thursday (AEDT), with Drew Mitchell and Kurtley Beale expected to replace Horne and Folau.
The Wallabies have already qualified for the quarter finals but a win over the Welsh would give them an easier quarter final against either Japan or Scotland and avoid meeting South Africa or New Zealand until a potential final.