Havili is of Pākeha and Tongan descent and is the son of former Nelson Bays rugby representative Bill Havili. David was born in the town of Nelson on New Zealand's South Island, but raised in nearby Motueka. He initially attended Motueka High School in his hometown, but later went to Nelson College, where he was a member of their 1st XV rugby team. After graduating high school he began working as a builder's apprentice while playing local club rugby for Nelson. During this time, he made his way through 's youth structures and was a member of the Knights Development team.
Senior career
Havili made the Tasman Mako squad for the first time in 2014, and burst onto the scene with 4 tries in 10 appearances for the men from Nelson as they reached the final of the ITM Cup Premiership before going down 36-32 to. He played all 11 of the Makos games in their run to the semi-finals in 2015, netting 31 points in the process. Tasman were again losing finalists in 2016 with Havili playing a key role with 2 tries in 10 games. During the 2019 season Havili captained Tasman to their first Mitre 10 Cup championship, scoring a try in the final win over Wellington.
Super Rugby
As a result of his impressive displays in his debut season at provincial level, Havili was named as a member of the Crusaders wider training group for the 2015 Super Rugby season. Somewhat surprisingly, he featured 11 times in his first season in Christchurch and helped himself to 2 tries which saw him promoted to the full squad for 2016. He made 14 appearances in 2016 and contributed 2 tries as the Crusaders reached the competition's quarter-finals before going down 42-25 to the in Johannesburg. In October 2016, it was announced that he had signed a new 3-year deal which would see him stay with the Crusaders through to the end of the 2019 season. Havili started at inside centre against the touring British and Irish Lions in 2017, slotting into the place of the injured Ryan Crotty. Havili's 80-minute performance did not see him score any points, as the Crusaders lost to the Lions 3-12. In the 2017 Super Rugby season, Havili was a key member of the Crusaders squad that lost only one match on the way to their eighth Super Rugby title. Havili was one of the Crusadees' stand-out performers in the 2017 season, not only displacing All Blacks 60-plus-test veteran Israel Dagg from the fullback position, causing Dagg to be shifted to the right wing upon his return from a knee injury, but was also voted the Crusaders' 'Player of the Year' for 2017. Havili was one of the leading try-scorers of the 2017 Super Rugby season, finishing with 8 tries. Winger Seta Tamanivalu was the only Crusader to score more tries than Havili, scoring 10 tries in 2017.
International
Havili was a member of the New Zealand Under 20 side that finished 3rd in the 2014 IRB Junior World Championship in his home country. He was not named in the initial squad, but was later called up to replace the injured Simon Hickey. Havili was called up to the All Blacks for the 2017 Rugby Championship squad after shoulder surgery ruled out Hurricanes back Jordie Barrett for the rest of the year. Havili made his All Blacks debut against the Pumas on 1 October 2017 at Estadio Jose Amalfitani, Buenos Aires, replacing in-form winger Rieko Ioane with only 10 minutes left of the match. Havili still one of the best performing All Blacks on his debut despite only 10 minutes of game time, scoring a try on his debut in the last minute of the test, allowing the All Blacks to beat Los Pumas 39-22. His standout performance against Argentina saw him named on the bench the following week against South Africa where he replaced the injured Nehe Milner-Skudder shortly before half time. Havili was the best-performing substitute off the bench in that fixture, setting up Damian McKenzie's try to make the score a 25-24 win over the Springboks for New Zealand. Havili played in three games on the 2017 end-of-year tour, the first of which was a quiet performance in a 23-18 loss to the Wallabies where he replaced Lima Sopoaga off the bench. Havili earned his first start for the All Blacks on 5 November 2017 in a 31-22 win over the Barbarians where he was replaced by Sopoaga in the 46th minute. Havili also started for the All Blacks ten days later in a 28-23 win over a French XV where he produced a good performance and was not subbed off.
