Santner was born in Hamilton, New Zealand. His father, Wayne, is a former first-class cricketer. Santner's grandfather, Jack, also played first-class cricket. Santner has a younger brother, Ben, who is also a cricketer
Santner is married to his long-time girlfriend, Hannah. The couple have a daughter, Harper.
Santner started playing cricket at a young age. He played for Hamilton Boys' High School and the New Zealand Under-19 team. He made his debut for Northern Districts in 2012.
Santner made his international debut for New Zealand in a One Day International (ODI) against England in June 2015. He made his Test debut against England the following month. He made his T20I debut against Bangladesh in February 2016.
Santner has played 87 ODIs for New Zealand, scoring 1,319 runs at an average of 21.98 and taking 88 wickets at an average of 34.61. He has five ODI half-centuries and two five-wicket hauls.
Santner has played 66 T20Is for New Zealand, scoring 569 runs at an average of 15.19 and taking 59 wickets at an average of 24.69. He has two T20I half-centuries and one four-wicket haul.
Santner has played 47 Tests for New Zealand, scoring 1,673 runs at an average of 25.31 and taking 111 wickets at an average of 39.17. He has four Test half-centuries and five five-wicket hauls.
Santner has captained New Zealand in three T20Is. He led the team to victory in one match and defeat in two matches.
Santner has not been involved in any major controversies during his career.
Mitch Santner is one of the most versatile cricketers in the world. He is a valuable asset to the New Zealand team in all three formats of the game. Santner is still relatively young and has the potential to achieve even greater things in his career.