Adam is the son of a former Junior All Black, Braeden Whitelock, and the grandson of All BlackNelson Dalzell. He has three brothers All BlacksGeorge Whitelock, Sam Whitelock and Luke Whitelock. Despite never playing for the All Blacks Adam was the only brother to play for the All Blacks Sevens team. Notably he was also the only brother to play in the backs. All four Whitelock boys were educated in Fielding and played their junior rugby for Palmerston North High School Old Boys' Rugby Football Club. In his early days Adam was identified as a talented middle distance runner. Adam was the first of the brothers to move to Christchurch, moving to study accounting at the University of Canterbury in 2006. Former Crusaders coach Todd Blackadder commenting on Whitelock's well renowned professionalism and work ethic stated that "Adam is one of the hardest workers in this team. He is consistently the fittest member of the squad but still strives to become better every year."
Career
Provincial
Whitelock debuted for the Canterbury team in 2008 as a 22 year old against Wellington. He would go onto play 56 games for Canterbury playing a staple role in the team. Despite being in the reserves in the final of the 2008 Air New Zealand Cup, Whitelock and the Canterbury team would go on to win the title for the next 5 years setting a new precedent in NPC history.
Super Rugby
Whitelock made his Crusaders debut against the Brumbies in 2009. His first try for the Crusaders was a crucial try from a brilliant pass from Leon MacDonald which led to the Crusaders overcoming the Stormers 11-7. In a remarkable occasion in professional sport teams all four Whitelock brothers played together for the first time in a competitive match in March 2013. Other than a preseason match at the beginning of the previous season this was the first time playing together since playing for Fielding High School in 2003. The brothers would play a further 17 games together at their time with the Crusaders.
All Blacks Sevens
In 2014 Whitelock was called into the All Blacks Sevens after receiving high praise in regards to his fitness from coach Sir Gordon Tietjens.
Overseas
Whitelock announced in 2014 that he was leaving New Zealand to take up a contract in France with Aviron Bayonnais.