Starting out competing on the Great Britain Junior Modern Pentathlon team, David Pearson made the switch to triathlon at the age of 17.  Qualifying for the first time at British Sprint Triathlon Championships, he made his international debut in Chicago finishing 10th in the 16-19AG.

After recovering from a heavy crash at the 2017 European Championships in Düsseldorf, he hit his stride with a maiden silver at Glasgow 2018. It was to become the first of a run of 5 podium finishes, including a gold at European Sprint Triathlon Championships in Kazan, Russia. At the 2018 European Sprint Duathlon Championships in Ibiza silver was upgraded to gold thanks to Spaniard Joan Mercade Cuadrat who, in an act of great sportsmanship, chose to voluntarily disqualify himself after accidentally cutting a small section of the bike course.

A member of Oxford University Triathlon Club, David maintains training links to Oxfordshire, Surrey and Cambridgeshire.