New Zealand coach Gary Stead said Santner was an obvious choice for the role.
“Mitch is a fantastic team man and leads by example in all facets of the game,” Stead noted.
“He’s an incredibly calm and collected personality and he has a huge amount of respect in the changing room, which will serve him well.
“He’s had plenty of experience leading the T20 side and did a good job when he captained the ODI team last month, so he already has a good understanding of what it means to lead the team.
“I’m sure Mitch will also bring his own ideas and style of leadership to the role.”
Santner’s first task in his new role will be captaining the side for six white-ball fixtures against Sri Lanka on home soil from December 23, with an ODI series in Pakistan in February also on the agenda ahead of next year’s ICC Champions Trophy event.
