Published: 2018-12-22 04:52:10 BdST
Smith, along with vice-captain David Warner and opening batsman Cameron Bancroft, was suspended for his part in the ball-tampering incident which shocked the cricket world and torpedoed Australia's sporting reputation.
Facing Australian media for the first time since his teary apology at a news conference at Sydney airport on March 29, Smith said he had learned of the plan when he overheard a conversation in the team's dressing room at Newlands.
"I think it’s been documented pretty heavily, sort of, what went on," he told reporters at the Sydney Cricket Ground.
"For me in the room, I walked past something and had the opportunity to stop it and I didn’t do it and that was my leadership failure.
"It was the potential for something to happen and it went on and happened out in the field.
"I had the opportunity to stop it at that point rather than say, 'I don’t want to know anything about it' and that was my failure of leadership. And you know I’ve taken responsibility for that."
Smith declined to name the players involved but reiterated that he had told them, "I don't want to know about it", and then walked away.
Smith has kept a low media profile since the scandal, despite playing at Twenty20 tournaments in Canada and the Caribbean, and turning out for his Sydney club side Sutherland.
However, in recent weeks he has made gradual moves to rehabilitate his public image and joined his former Australia team mates at training sessions.
Smith has also tested the waters to see how his brand power has fared in the wake of the incident, linking up with the local arm of Britain's Vodafone Group to shoot an advertisement which played on his shame and hopes of redemption.
The commercial, and Smith's involvement in it, was criticised by some media pundits and generated mixed responses on social media.
Smith said he was getting paid for the campaign but also "putting forward" funds from it to Gotcha4Life, a local men's mental health charity.
The 29-year-old added that it had been tough at times watching Australia play from the sidelines and said he was determined to break back into the one-day side for the May 30-July 14 World Cup and the Test team for the Ashes beyond that.
"I’m just moving forward day to day, doing what I need to do to prepare to hopefully get another opportunity to play for Australia and if that's the World Cup and Ashes, so be it," Smith told reporters at the Sydney Cricket Ground.
"No doubt the English crowd will be incredibly hostile. I'm ready for that if that happens.
"I'll keep working hard and if I get that opportunity again, that'd be great."
Australia, led by Smith's replacement as captain Tim Paine, are tied 1-1 in a four-Test series with India ahead of the third contest in Melbourne starting on Boxing Day.
Smith and Warner's bans will be lifted at the end of March, with Bancroft's expiring on Dec 29.