He had the top job in 2000-01 but would concede he is now better equipped for the role than he was then.
Success has followed Smith wherever he has set up camp, dating back to his time as coach of the Crusaders in the late 1990s where he won a pair of Super Rugby crowns. He was also an assistant under Graham Henry with the All Blacks from 2004-2011 and helped capture the 2011 cup.
The path for Smith to return to the All Blacks was paved when Hansen shifted (Brian) Aussie McLean from the defensive portfolio to an analyst position.
Hansen approached Smith with a serious offer earlier this year but the Waikato-based coach made a decision only a few weeks ago following consultation with his family.
"The fact that it's a World Cup year, for me personally, I got a lot of satisfaction from the last one and it was something that my family and I had worked for for eight years and it was a dream come true," Smith said of the 2011 victory.
"So for me now if others can have that same experience, and I can help them, then that'd be great."
Smith will join a coaching battery that includes Hansen, assistant Ian Foster and specialist coaches Mike Cron (forwards) and Mick Byrne (skills) as the All Blacks look to defend their World Cup title in England and Wales in October.
"Your role as a coach is to help others get better and that means lifting them up, helping to encourage them and trying to equip them with tools so they can win under pressure."
A collection of senior All Blacks, including Ma'a Nonu, Kieran Read, Conrad Smith and captain Richie McCaw, also helped influence Smith's decision to return to the fold.
"When you go in to an environment you want to make sure that you have a positive impact and that people think you can make a difference," he said.