The 24-year-old has been with Edinburgh since 2015 and has made more than 100 appearances as well as being capped 28 times for Scotland.
Mike Blair's side are a point behind leaders Leinster in the United Rugby Championship rankings this season and Kinghorn believes they are destined for big things if they continue their improvement.
"I'm really happy to be staying with Edinburgh for the future and looking forward to what it holds," he said.
"I feel you can see this season the boys and management, the whole club and fans are pulling as one in the same direction. I love the growth I can see in this club.
"I feel like we are starting to see it now and that I can really add something to that.
"You can see in our results we have been going really well and I feel there is so much more growth in the team. We have such an exciting squad, a lot of depth in our squad.
"I am just happy to be part of it and I feel like we can go on and achieve something special and hopefully win some silverware.
"I'm an Edinburgh boy born and raised so it's nice to stay in your home city. I have grown up in Edinburgh all my life and been an Edinburgh fan, going to the games when I was younger, so to extend my contract is something I am really happy about."
Kinghorn has recently switched from full-back to stand-off and the likes of Adam Hastings have been helping him grow accustomed to the new role.
"It's always a learning process, having played in the back three for most of my career," he said.
"But Mike and all the other coaches have been really good, Mike and Gregor (Townsend) especially. And all the other 10s in Scottish rugby have been helping me along.
"All the boys have been really good. It's handy having Hasto, one of my best pals, as an international world-class 10. He is helping me along.
"(The Scotland) camp was really good, a really good learning point for me, being around different people and seeing how they operate and what they see in the game, different pictures in what they are thinking. Just trying to pick their brains really.
"It's something I am really enjoying - I find it really exciting to try and learn a new position and try and get the most out of myself in that position, which I feel I can do."
Kinghorn is working his way back from a quad injury but has only missed one match so far with both games of Edinburgh's festive double header against Glasgow now postponed.
"I am hopeful I will be fit in the next couple of weeks," he said.