Businessmen Phil and Ashley Kirk made the exciting announcement at the club’s AGM on Wednesday night.
Chairman Mike Goodwin said the successful brothers want to invest in the club in a ‘significant way.’
Ashley, who still lives in Chesterfield, will join the board.
Chesterfield re-sign former Notts County goalkeeper who has recently been playing European football
How Chesterfield could line-up against Aldershot Town
Recap: Liam Mandeville scores second-half winner against Aldershot Town
Chesterfield were 'worthy winners' against Aldershot Town
Why Chesterfield manager Paul Cook will continue to not select a goalkeeper on bench
Goodwin said that neither of them want any shareholding in the club and that they are ‘happy’ with the current community model.
Half of the £1m will go on ‘general’ matters and the other half will go on helping to build the planned supporters bar.
Some of the funds will be used to help manager Paul Cook immediately strengthen the squad before Thursday’s transfer deadline.
Goodwin said the club was in ‘negotiations’ about bringing in one or two players.
Phil’s background is in oil and he stepped down from his role as executive director at Harbour Energy at the start of February to ‘consider other business opportunities.’
According to the Financial Times, Phil was the founder of Harbour Energy group’s predecessor, Chrysaor, and helped turn it into the ‘biggest oil and gas producer in the UK North Sea following multibillion-dollar acquisitions including the bulk of Shell’s and ConocoPhillips’s UK assets.’
The FT states that Phil owns a 1.4 per cent stake in Harbour, which has a market capitalisation of £3.36bn.
Phil said: "We have agreed to put £1m into the club.
"My wife does know!
"Paul Cook has promised not to waste it! We had a really good chat with him.
"Half of the money is going to go into the general and then half of the money at the moment we are looking to help build the sports bar.
"I left Chesterfield in the mid-80s.
"Ash has lived here all of his life and is still here.
“I am so proud of the town, proud of Chesterfield, proud of Derbyshire and proud of the team.
"Just to be able to put some money in and help is great.
"Our only wish is to do good for the town and for the club.
“Ash is going to go on the board of the club.
"We have sort of rushed it for the (transfer) deadline which is just coming up.
"I know Paul (Cook) is looking at a few ideas so we will keep our fingers crossed it will make a difference in the last few games.
"There are no skeletons – look me up, it is all good.”
Brother Ashley, who lives in Ashgate, whose background is in recruitment, added: "I have lived in Chesterfield all of my life.
"I had a business which I ran for 30 years. I was lucky enough to be able to sell it in December. I was fortunate enough to make some money and get out.
"Many of my family and friends are season ticket holders and I am pleased to be on board.
"My commercial background is running tight budgets, making a profit, my business had a turnover of about £25m when we sold, so hopefully I will be able to help.”