He has signed a two-year deal and will join just the third club of his senior career when the current campaign finishes.
The veteran midfielder has turned out more than 600 times in 14 years with Celtic since joining from Hibs in 2007, winning 22 trophies with the Hoops.
There had been much speculation about the 35-year-old’s future plans with his contract set to expire in the summer and he was tipped to team up with former team-mate Stephen Glass at Aberdeen
The ex-Hibs and Dons winger was appointed earlier this week, fuelling rumours that Brown could be heading north to take up a new role with Aberdeen.
Welcoming Brown’s decision, Glass said: “The opportunity to bring a player of Scott’s calibre is a huge coup for me and for Aberdeen.
“His experience will be invaluable on the pitch and he is someone who will help set the standards we expect at this club. A born competitor, with a strong appetite to win, his hands-on approach and desire to nurture will hugely benefit the development of the young, emerging talent we have here.
“Scott will be a big part of my coaching team and whilst his impact will undoubtedly be felt on the pitch where I believe he still has much to give, I am looking forward to assisting his transition into coaching.”
Brown told Aberdeen’s website: “There is no doubt I had a lot to deliberate when deciding my next steps, particularly after enjoying fourteen successful years at Celtic. However, the opportunity to join Aberdeen, a club entering an exciting new period with my former team-mate Stephen now at the helm, was one I couldn’t pass up.
“Once this season concludes, I’m looking forward to joining Stephen, the playing and coaching staff and everyone at Aberdeen FC. I am totally committed to the challenge that lies ahead in meeting the ambitions of the club and its fans.
“I still feel I have got a lot to give, not only on the pitch, but in a broader capacity as I embark on my coaching journey. I will be relentless in my quest for success for Aberdeen.”