Uncapped Faumuina named in All Blacks squad
The 25-year-old Faumuina missed the Test series against Ireland in June through injury but was singled out for praise by Hansen for his patience and determination.
"He had to wait a while to get over his calf injury before he could be selected officially by the All Blacks so it will be exciting for him and his family," said the coach.
"He's an outstanding front rower and we look forward to seeing him play at the next level."
Hansen said the world champion All Blacks would need to improve in the Rugby Championship despite bullying Ireland in a 3-0 series whitewash.
"We are all looking forward to the new championship and the various challenges that it will bring," he said. "But we also know we will need to step up from where we were in the recent series.
"We now have the opportunity to take our game to the next level. The three best teams in the world will be playing each other and with Argentina joining in for the first time it's going to be hugely exciting."
Outside back Cory Jane, who missed the Ireland series with an ankle injury, returns and loose forward Liam Messam has also been selected.
A replacement for the injured Conrad Smith will be confirmed next week with 17-Test All Black Sonny Bill Williams the likely choice.
The competition starts on August 18.
Backs: Israel Dagg, Hosea Gear, Cory Jane, Ben Smith, Julian Savea, Conrad Smith, Ma'a Nonu, Tamati Ellison, Aaron Cruden, Daniel Carter, Piri Weepu, Aaron Smith.
Forwards: Kieran Read, Victor Vito, Richie McCaw (captain), Liam Messam, Adam Thomson, Sam Cane, Sam Whitelock, Luke Romano, Brodie Retallick, Owen Franks, Ben Franks, Charlie Faumuina, Wyatt Crockett, Tony Woodcock, Andrew Hore, Keven Mealamu.