NZC general manager of high performance Bryan Stronach said a split coaching model was considered and rejected, though flexibility remained to co-opt additional coaching staff if necessary.
Stead was first appointed in 2018 and this is his second contract extension. His current contract was due to expire after the upcoming men's Cricket World Cup in India. He will stay on until the end of the current World Test Championship cycle in 2025.
"The support for Gary was overwhelmingly positive from the players, the Black Caps support staff, major association coaches and support staff as well as the New Zealand Cricket Players Association and NZC High Performance Unit staff," Stronach said.
"Gary's results have been very impressive and we're confident that he still has a lot to offer the team. Of course, a big part of this decision came down to whether Gary wanted to continue and he made it clear his appetite to take this team forward was as keen as ever."
Stead has led New Zealand to the first World Test Championship title and to the finals of the 50-overs and Twenty20 World Cups.
Black Caps captain Tim Southee said the players were eager for Stead to continue.
"Gary's had great success leading us into finals in all three formats and, of course, that World Test Championship win," Southee said.
"It's been great the way that he's come in and built on what was previously achieved."
