Drysdale began competing at World Cup level in 2002, in the New Zealand coxless four. After the 2004 Olympic Games, in which his New Zealand crew finished fifth in the final, Drysdale switched to the single scull, winning the 2005 World Championships at Gifu, Japan, despite having broken two vertebrae in a crash with a water skier earlier in the year. He successfully defended his title in 2006 at Dorney Lake, Eton, England, in 2007 at Munich, Germany, and again in 2009 in Poznań, Poland, holding off Britain's Alan Campbell and Czech Republic's Ondřej Synek. At the 2009 World Rowing Championships he also beat his own World Record in the single and reduced it to 6:33.35.
Olympic Games
At his first Olympic Games, in 2004, Drysdale was part of the New Zealand coxless four team that finished fifth. Drysdale was officially selected as New Zealand's Olympic heavyweight sculler for the Beijing Olympics on 7 March 2008. He was also chosen to carry the flag for New Zealand during the parade of nations in the opening ceremony. Unfortunately for Drysdale, a severe gastrointestinal infection in the week before his final saw him off form and he was only able to win the bronze medal in the men's single scull. The gold and silver medals went to Olaf Tufte from Norway and Ondřej Synek from the Czech Republic, respectively. Clearly suffering from his illness, after his race Drysdale was carried by life raft and then moved to a waiting ambulance. He was also seen vomiting. He was, however, able to stand to be awarded his medal. At the 2012 Summer Olympics Drysdale won the gold medal in the men's single sculls, despite throwing up the morning of race day due to nervousness. He has since been dethroned, and had to settle with silver in the world championships leading up to the 2016 Olympics, each time bested by the Czech Ondřej Synek, who won the WC in 2010, 2013, 2014 and 2015. At the 2016 Summer Olympics, Drysdale successfully defended his Olympic men's single sculls title, taking the gold medal over Croatia's Damir Martin. The race was decided by a photo finish, with Drysdale edging out Martin by half a bow ball. In November 2016, Drysdale announced that he would take a break from rowing in 2017. He returned to the New Zealand squad at the end of 2017 with a view of competing at the 2020 Tokyo Olympics.
Drysdale won the 2006 Sportsman of the Year award and took out the supreme Halberg award. He was again voted Sportsman of the Year in 2007, 2009, 2012, and 2016, and is the only New Zealander to have won the award more than three times. He won the University of Auckland Young Alumnus of the Year Award in 2007, and was awarded Member of the New Zealand Order of Merit for services to rowing in the 2009 New Year Honours. Drysdale won the Sportsground.co.nz Sportsman of the Year award in 2008.
Canoe polo
Drysdale has also represented New Zealand in canoe polo as a junior. He represented NZ in an under-18 team that toured to Fiji. Later he was a NZ under-21 representative that toured to Tonga. In 1999–2000 he was executive of NZ Canoe Polo.
