Born: April 25, 1983
Coach: Ron Warhurst
Previous Olympics: 2008 (silver), 2012, 2016 (bronze)
Willis heads to his fourth Olympic Games in Tokyo, looks for his third medal, but first gold.
The Kiwi made a successful start to his career, when he broke Sir John Walker's 32-year-old national record for 1500m at the Golden League series event in Paris in 2005, backing that up with a gold medal at the 2006 Commonwealth Games.
After originally finishing third, Willis won a silver medal at the 2008 Beijing Olympics, after winner Rashid Ramzi failed a drug test and was stripped of his title.
In 2010, Willis was forced to have knee surgery, but recovered in time to claim a Commonwealth Games bronze medal at Delhi.
Willis was the flag bearer at the 2012 London Olympics and qualified for the final as the oldest runner, finishing ninth.
He returned to the podium at the 2014 Glasgow Commonwealth Games, thanks to a brilliant preparation, where he ran career best times over four different distances. Willis passed South African Johan Cronje with his last three strikes to claim bronze.
The Wellington native started the 2016 season strongly with his first world indoor championship medal, claiming bronze, before qualifying for his third successive 1500m Olympic final.
Willis produced a magnificent performance to claim third and his second Olympic medal, becoming the oldest man to win a medal in the 1500m.
At the start of 2021, Willis broke the four-minute mile for a record 19th year in a row, breaking a tie with Sir John Walker.
Willis and brother Steve are the only brothers in New Zealand history to have both broken the four-minute mile.