Acting ARU Chief executive officer Matt Carroll claimed it had been a "smooth and straightforward process" to re-sign the Wallabies' openside flanker.
Friday's announcement means Pocock, who has represented Australia on 45 occasions, will be available to play for the Wallabies when the British and Irish Lions tour next year.
He is also now likely to be the man to skipper Australia at the 2015 World Cup.
"It really is great news to have him on board not only for next year's Lions Tour but the next Super Rugby Championship series and, quite possibly, the next Rugby World Cup in 2015," Carroll said.
Pocock will line-up for the ACT Brumbies in next year's Super Rugby season, after six seasons with the Western Force.
The 24-year-old revealed he was looking forward to his new challenge, writing on his Twitter page: "Happy to announce I've signed with the ARU for another three years. Excited about next season with @BrumbiesRugby!"
Brumbies coach Jake White is confident the 24-year-old flanker will fit into his team "perfectly", while he considers the capture of Pocock as something the Canberra-based side can be proud of.
"To have a guy like David Pocock want to be involved with the Brumbies is very encouraging," White said.
"The attitude and commitment of Brumbies players both during 2012, and as we prepare for 2013, has been outstanding. I see David thriving in this environment. He will fit in here perfectly. At the end of the day, we want to make David a better player."