Born in Palmerston North and raised on a dairy farm in the suburb of Linton, 11 km south-west of the city, Luke was born into a rugby household with his grandfather being 1950's All Black, Nelson Dalzell, father Braeden being a former Manawatu and New Zealand Colts representative and 3 older brothers; George, Adam and Sam all going on to play for Canterbury and the Crusaders with George and Sam also becoming All Blacks.
After attending a local primary school, Whitelock was sent to Feilding High School as a boarder and while there played first XV rugby, captaining the side in his final year. Following his graduation from high school, he moved south to attend university in Christchurch and began playing local club rugby for the University of Canterbury. He was also took a gap year at Loughborough Grammar School for a year.
Whitelock first made the Canterbury squad at the age of 20 ahead of the 2011 ITM Cup and went on to play 4 times during his first season of provincial rugby, earning his first ITM Cup Premiership winners medal as his side defeated Waikato 12-3 in the final. The following year, having gained some Super Rugby experience with the Crusaders, he became much more of a regular in Canterbury's starting XV, this time featuring 9 times and scoring his first ever provincial try as the men in red and black retained their ITM Cup title, this time overcoming Auckland 31-18 in the final.
2013 saw him win his 3rd ITM Cup in 3 years as Canterbury finished 2nd behind Wellington on the Premiership log, but were able to overcome the Lions 29-13 in the final. Whitelock scored 3 tries in 10 games to help Canterbury lift their 6th ITM Cup in a row. However, they were unable to hold on to their title in 2014, going down to local rivals, Tasman in the semi-final with Whitelock featuring in all 11 of their games during the year.
Ahead of the 2015 ITM Cup, he was named as Canterbury captain, following in the footsteps of older brother, George, who led the Cantabrians to five successive national titles between 2009 and 2013. Luke's captaincy got off to the perfect start as Canterbury went through the regular season with a record of 9 wins and 1 loss and after defeating Taranaki and Auckland in the playoffs they were crowned ITM Cup champions once again. It was a title they held onto in 2016, with the competition renamed the Mitre 10 Cup, but Whitelock still captaining a star-studded Canterbury side, they once again finished top of the Premiership log and after overpowering Counties Manukau in the semi-finals they gained revenge on Tasman for their 2013 semi-final loss by defeating them 43-27 in the final, making it 8 championships in 9 years.
Impressive displays in his debut season for Canterbury in 2011 saw Luke become the fourth Whitelock in the Crusaders Super Rugby squad for the 2012 season. Despite fierce competition for places among the franchise's loose forwards, he was able to get plenty of game time in his first season at Super Rugby level, playing mostly off of the replacements bench, he featured 10 times as the Crusaders, beaten finalists in 2011 made it to the competition semi-finals before going down 20-17 to New Zealand rivals and eventual winners the Chiefs.
In 2013, he played in all 18 of the Crusaders matches as they were once again eliminated at the semi-final stage by the Chiefs who went on to defend their title by defeating the Brumbies in the final. While in 2014 despite competing for a starting place with the likes of; Richie McCaw, Kieran Read and Jordan Taufua, Whitelock started a then career high 10 times and scored 2 tries to help the Crusaders make the Super Rugby final where they narrowly went down to the Waratahs in Sydney, losing 33-32.
2015 would prove to be his final year with the Crusaders and it would also be his least productive with the franchise, starting just twice out of a total of 8 appearances as the men from Christchurch endured a disappointing campaign and finished in 7th place, just missing out on the playoffs. The Highlanders were the competition's form team in 2015, defeating the Hurricanes 21-14 in the final and to bolster their squad ahead of their title defense in 2016, they announced that Whitelock would be moving south to join them ahead of the 2016 season. He started 12 times in his first season in Dunedin as his new franchise failed to retain their Super Rugby title, bowing out 42-30 to the Lions in the semi-finals.
Whitelock was a New Zealand Schools representative in 2008 and was also a member of the New Zealand Under−20 sides which lifted the IRB Junior World Championship in 2010 and 2011, captaining the side in 2011 and playing a total of 9 games across both tournaments.
He earned his first call up to the senior New Zealand side ahead of the 2013 end-of-year rugby union internationals and debuted as a second-half replacement for Dominic Bird in a 54-6 victory over Japan in Tokyo.
On 5 November 2016, Whitelock featured in the number 8 jersey for the Barbarians in their 31-31 draw against South Africa at Wembley Stadium. He played all 80 minutes in a side which contained former Crusaders teammates Jordan Taufua and Andrew Ellis.
New Zealand Under-20IRB Junior World Championship - 2010, 2011
CanterburyNational Provincial Championship - 2011, 2012, 2013, 2015, 2016
As of 11 January 2017