A two-time Olympic medallist, Jonathan Brownlee began his career as the 2006 and 2007 British Youth Champion in both triathlon and duathlon. In 2008, he won bronze medals at the ETU European Junior Triathlon Championships and ITU World Junior Championships, and placed 17th in his ITU World Championship Series debut event in Kitzbühel.
During the 2009 season, Brownlee won gold at the Australian Youth Olympic Festival and competed in two races in the 2009 ITU World Championship Series, finishing 13th in Kitzbühel and 27th in London.
In 2010, Brownlee represented French club ECS Triathlon in the prestigious French Club Championship Series Lyonnaise des Eaux Grand Prix
Despite suffering a 15-second penalty, Jonathan took the bronze medal at the London 2012 Olympic Games, his brother Alistair taking the gold. Two years later he was part of the GB Mixed Relay team that won Commonwealth Games gold, alongside Alistair, Vicky Holland and Jodie Stimpson.
In 2015, Jonathan won the World Triathlon Gold Coast and World Triathlon Auckland, following up with a successful 2016 that saw a brilliant second place at the Rio de Janeiro Olympic Games and going on to win the World Triathlon Edmonton, finishing second in the overall rankings behind Mario Mola.
2017 brought a gold medal at the ITU World Triathlon Stockholm and five top-5 WTS finishes in all, resulting in a sixth-place ranking at the end of the season. Despite disappointment at his home World Series race in Leeds, Jonathan Brownlee had another consistent 2018 with four top-10 finishes and silver in the Lausanne World Cup, finishing 11th in the overall rankings by the end of the year.
- 4th place 2018 ITU World Triathlon Hamburg
- 2nd place 2018 Commonwealth Games Mixed Relay
- 5th place 2018 ITU World Triathlon Edmonton
- Winner 2017 ITU World Triathlon Stockholm
- 2nd place 2017 ITU World Triathlon Leeds
- 5th place 2017 Rotterdam World Triathlon Series Grand Final
- 4th place 2017 ITU World Triathlon Montréal
- 4th place 2017 ITU World Triathlon Edmonton
- 2nd place 2016 ITU World Triathlon Grand Final Cozumel
- Winner 2016 ITU World Triathlon Edmonton
- 2nd place 2016 ITU World Triathlon Stockholm
- 2nd place Rio 2016 Olympic Games
- 3rd place London 2012 Olympic Games
12019 ITU World Triathlon Edmonton 20 Jul, 2019 - Elite Men - 00:54:52
DNF2019 Hamburg Wasser World Triathlon 06 Jul, 2019 - Elite Men - DNF
352019 AJ Bell World Triathlon Leeds 08 Jun, 2019 - Elite Men - 01:48:57
112019 MS Amlin World Triathlon Bermuda 27 Apr, 2019 - Elite Men - 01:51:54
82018 ITU World Triathlon Grand Final Gold Coast 12 Sep, 2018 - Elite Men - 01:45:51