Cricket Australia chief executive James Sutherland met with the disgraced trio behind closed doors at the team hotel in Johannesburg, and confirmed the bans late last night.
Significantly, Smith will not be considered for the captaincy or a leadership role for a minimum of two years, while Warner - the instigator of the ball-tampering plan - will not be considered for any leadership roles in the future.
In a statement, Cricket Australia noted that any consideration of Smith returning to the captaincy after the two years would "be conditional on acceptance by fans and the public, [and] form and authority among the playing group."
Smith and Warner have already been removed as captain and vice captain respectively of the Australian test side, and are being sent home from South Africa before the final test, along with Bancroft. Matthew Renshaw, Joe Burns and Glenn Maxwell were called up as their replacements.
Both Smith and Warner had also already stood down from their respective roles as captains with their Indian Premier League squads, and have now been banned from participating in this year's event - costing them both millions of dollars.
"The players that they have banned, we are also barring those two players from this season," IPL chairman Rajeev Shukla told reporters. "The franchises will get replacements for the players."
Sutherland said he felt the length of the bans found an appropriate balance.
"I am satisfied that the sanctions in this case properly reflect a balance between the need to protect the integrity and reputation of the game and the need to maintain the possibility of redemption for the individuals involved, all of whom have learned difficult lessons through these events.
"Cricket Australia will provide more details of an independent review into the conduct and culture of our Australian men's team in due course."
Darren Lehmann remains coach of Australia, with CA's investigation team finding that no coach or member of support staff knew of the ball-tamping ploy, and that Smith, Warner and Bancroft were the only players aware.
For Smith and Warner, those sanctions are set to see them sit out a year before returning in time for the 2019 Cricket World Cup and Ashes series - though Warner's international future is in serious doubt - while Bancroft won't play international cricket for nine months.
Tim Paine will take over as Australian captain, and Smith, wearing a white T-shirt and dark baseball cap, hugged Paine as he prepared to leave the team hotel in Johannesburg to fly home on Wednesday.
Smith will hold a media conference when he lands in Sydney, while the players have the option to challenge the verdict.
