Guptill was born in Auckland in 1986. He attended Kelston Primary and Kelston Boys’ High School before transferring to Avondale College where he played cricket and was prefect. His wife is journalist and reporter Laura McGoldrick whilst his cousin, Michael Guptill-Bunce, has also played cricket for Auckland.

In domestic cricket, Guptill plays for Auckland, and for Suburbs New Lynn in club cricket. He made his first-class cricket debut in March 2006, scoring a four-ball duck in his first innings, and 99 in his second. In 2011 Guptill played in English county cricket during the second half of the season for Derbyshire County Cricket Club.

Guptill first represented New Zealand in the Under-19 Cricket World Cup held in Sri Lanka in 2006. He made his One Day International (ODI) debut for New Zealand on 10 January 2009 against the West Indies in Auckland, becoming the first New Zealander to score a century on his one-day debut – his score of 122 not out is the highest score on debut for New Zealand in an ODI, and second highest debut score ever in ODIs and he was the first New Zealander to carry the bat through a completed ODI innings. He made his Test cricket debut against India in the first Test at Hamilton in March 2009, scoring 14 and 48. For his performances in 2009, he was named in the World ODI XI by the ICC.

Guptill’s first international century was made in his New Zealand debut in an ODI against the West Indies at Auckland in 2009. Guptil’s innings of 122 not out was described as “one of the best I’ve seen in a long time” by the New Zealand captain Daniel Vettori. His century was the first by a New Zealander on their ODI debut. He went on to make the highest ODI score by a New Zealander at Southampton in June 2013, scoring 189 not out against England. At the time the score was the fifth highest in any ODI and equalled the highest individual score made against England.

Guptill surpassed his best score in the 2015 World Cup, scoring an unbeaten 237 from 163 balls against West Indies in the quarter-finals at the Westpac Stadium in Wellington. He was the first player to score a double century in a knockout stage match as New Zealand scored 393, the best total in a World Cup knockout match. After scoring three ducks in group matches he ended the tournament with 547 runs, emerging as the highest scorer.

Guptil went on to set a new ODI record for New Zealand when he made the highest score of his career, 237 not out in the 2015 World Cup against West Indies at Wellington. The innings was the second highest scoring individual innings in ODI history and remains Guptill’s highest score in any form of cricket. His other double-century was made playing for Derbyshire in a 2015 County Championship match at Bristol. This is his only first-class double century as of January 2019.

Guptill played for Mumbai Indians in the 2016 Indian Premier League as a replacement for the injured Lendl Simmons. and for Kings XI Punjab in the 2017 Indian Premier League. In December 2018, he was bought by the Sunrisers Hyderabad in the player auction for the 2019 Indian Premier League.

In May 2018, he was one of twenty players to be awarded a new contract for the 2018–19 season by New Zealand Cricket. In April 2019, he was named in New Zealand’s squad for the 2019 Cricket World Cup.

In July 2019, he was selected to play for the Edinburgh Rocks in the inaugural edition of the Euro T20 Slam cricket tournament. However, the following month the tournament was cancelled. He was released by the Sunrisers Hyderabad ahead of the 2020 IPL auction.