Tim Sherwood's side set up a final showdown with Arsenal after goals from Christian Benteke and Fabian Delph stunned Liverpool 2-1 on Sunday.
Villa fought back from Philippe Coutinho's opener to reach their first FA Cup final since 2000 as they chase their first silverware for 19 years.
Fox joined Villa from the Gunners, where he was chief commercial officer, last summer and, while he insisted the club have a long way to go after their battles with relegation, hopes their struggles are nearing an end.
He said: "This is something which can create a positive atmosphere and blows through the negativity and clears it out
I hope it is the beginning of something great
If we play the way we played on Sunday I think we'll have a chance.
"Here we are heading into a final with another great club
That's the company Villa needs to keep and hopefully where we can put the club.
"We have a lot of work to do, I have been very honest about that
We have a lot of work to do to put the club back into a place where this is a thing we can do on a much more regular basis.
"Greg Dyke (Football Association chairman) made a speech before the game and I wish all of our fans could have heard it
He talked about the history of Liverpool and Villa, seven FA Cups apiece all the semi finals we've been in and he talked about the club in a way the fans still see the club and a way we want people to see it."
Victory in the final would put Villa into the Europa League but Fox is not focused on a possible European campaign yet.
He said: "It could be great, I wasn't envisaging it that way
I thought we'd build to it more slowly but the thing would be winning the FA Cup
It would be a such a positive emotional driver for what we want to do
I am more focused on that than what it means for Europa League qualification."
Chairman Randy Lerner was unable to make the game after his aunt passed away but he will be at Wembley for the final.
Fox added: "He had a family bereavement
He has a very small family and his mother's sister passed away and he wasn't able to make it.
"What does he think about it? He's ecstatic, I have emails on the phone
He will be here for the final
He was pretty upset he couldn't be here."
Source : PA
Source: PA