The move is likely to present the openside flanker, who made his debut with the Force when they were established in 2006, with a greater opportunity to win the Southern Hemisphere's most prestigious club rugby title.
The chance to work under South African World Cup-winning coach Jake White from the 2013 season also played a part in his decision.
"The Brumbies have a good coaching and management team of Jake White, Laurie Fisher, Stephen Larkham and Tony Thorpe," the 24-year-old told Australia's AAP.
"The opportunity to learn from them and challenge myself was appealing," said Pocock, who added that the move would also allow him to spend more time with his family.
"Over the last seven years, I have travelled long distances to visit my family in Brisbane," he said. "With the Wallabies schedule there is more and more of my time required on the east coast with training camps.
"Being based in Canberra will make it easier to travel to Brisbane and Sydney."
White said: "To have a guy like David Pocock want to be involved with the Brumbies is very encouraging. I see David thriving in this environment. He will fit in here perfectly."