The Slync.io CEO has revealed the deal has gone through with just 'small bits' left to do, while administrators Quantuma have since confirmed the news.
The Rams' ownership turmoil began in October 2020 when Mel Morris expressed his intention to sell the club, which was placed into administration in September 2021.
The lack of a new owner resulted in a total of 21 points deducted from the Championship side this season, with manager Wayne Rooney unable to overcome the odds and avoid relegation to League One.
But positivity for one of England's oldest football clubs looks just around the corner, as Kirchner revealed.
The American buyer posted on Twitter: "I've been beyond fortunate and I'll never forget how lucky I am. I've had the opportunity to realise many of my dreams and even a lot of things beyond my dreams.
"Today is a day I'll never forget. I'm humbled and excited to share that we've exchanged contracts with Quantuma and I will be the next owner of Derby County Football Club.
"These contracts are conditional on the sale of the stadium and some small bits. I don't anticipate any issues completing the rest of this process in the coming days. I'll begin funding the club next week.
"The membership agreement with the EFL is agreed to, we have filed with the FA to recognize the transfer and my team is now moving forward on the process to rebuild this iconic club.
"This has been a traumatic period for everyone and I can say that I hope this is the most difficult transaction I have to complete for a very long time.
"Thank you to so many of you for the kind words and support through this process. Tomorrow is the first day of a new journey together and I cannot be more excited to be a Ram."
A statement from Quantuma also confirmed the news. It reads: "A spokesperson on behalf of the joint administrators of Derby County Football Club said: During the course of the week since our last update, further significant progress has been made.
"As a result of this progress, the joint administrators can confirm that they have exchanged contracts for the sale of the business and assets of the club with preferred bidder, Chris Kirchner. Completion is targeted for on or before 31 May 2022. This is a very significant step towards the completion of a sale of the club.
"In addition, the joint administrators can confirm that in the interim period between exchange and completion, funding for the club is being provided by Mr. Kirchner, in a demonstration of his ongoing commitment to securing the long-term future of the club. "The exchanging of contracts is conditional on the sale of the stadium, EFL approval and receiving secured creditor consent.
"The period of time between exchange and completion will allow the joint administrators and all relevant stakeholders the time required to work together to meet the conditions required to complete this very complex transaction. "The joint administrators would like to express their thanks, to all relevant stakeholders for their co-operation and work, towards achieving a successful completion."