Rennie, who is of Cook Islands descent through his mother, becomes the first All Blacks Head Coach with Pasifika heritage.
NZR Chair David Kirk said Rennie has a proven track record as a successful head coach.
"On behalf of the Board, I'd like to congratulate Dave on his appointment as All Blacks Head Coach," he said as per allblacks.com.
"He is a world-class coach who has consistently shown he can build strong performance environments and win.
"Dave understands what it means to coach the All Blacks and play a style of rugby that reflects who we are as New Zealanders. He has a deep understanding of rugby in New Zealand and the role the All Blacks play in shaping our national identity and bringing communities together."
Rennie revealed it was a privilege to be appointed Head Coach of the All Blacks.
"Coaching the All Blacks is an incredible honour," said the 62-year-old.
"I'm extremely proud to have been entrusted with this role and understand the expectations that come with it.
"I'm really clear on the way I want the All Blacks to play and I look forward to working with the players, management team, and the rugby community. We have a lot of talent here and we will be working extremely hard to make the country proud."
Kirk said he believed the appointment process had been the most thorough the organisation has undertaken for an All Blacks Head Coach.
"The All Blacks are set for a challenging and exciting two seasons ahead and it's critical we followed a thorough process to find the right head coach," he continued.
"Dave has a clear direction for the team that gives us confidence the team will be well-positioned to perform as we head into the 2027 Rugby World Cup."
As All Blacks Head Coach, Rennie will honour his commitments with the Kobelco Kobe Steelers in Japan until the conclusion of the Japan Rugby League One competition, before returning to New Zealand to prepare the All Blacks for the July home series against France, Italy and Ireland.
Rennie is a highly respected head coach with success across New Zealand and international rugby. He led the New Zealand Under-20 team to three consecutive Junior World Championships between 2008 and 2010, guided the Chiefs to back-to-back Super Rugby titles in 2012 and 2013 and took the Glasgow Warriors to a Pro14 Final in 2019.
He has also delivered domestically in New Zealand with the Wellington Lions and Manawatu Turbos in the National Provincial Championship and was Head Coach of the Wallabies between 2020 and 2023. Most recently, Rennie has developed the Kobelco Kobe Steelers into title contenders in Japan Rugby League One.