Jacob Clear began kayaking in 2006 through surf lifesaving which he started at the age of five as a nipper. Clear won the U/19 single ski event at the 2003 Australian Surf Lifesaving Championships and won bronze in the open event the following year. In 2005 Clear was selected as part of a kayaking talent identification program. Switching his focus to sprint paddling, Clear won the U/23 K1 1000m and K1 500m in his second year in the sport at the 2007 National Championships. He then made his debut on the Australian team in 2007 and competed at the 2008 Olympic Games. Clear kayaked in the K2 500m in Beijing with Clint Robinson and placed 13th.
He returned to Olympic competition at the London 2012 Games having qualified as a part of the K4 1000m crew with Murray Stewart, David Smith and Tate Smith. Finishing 3rd in their heat, the team looked impressive as they topped their semi-final and headed into the Olympic final full of confidence. Leading by under a tenth of a second at the halfway mark, the Australians beat home the Hungarians by 0.61 seconds to win the gold medal. The crew was the only Australians to win gold at Eton Dorney at the London 2012 Games.
Four years later in Rio, Clear teamed up with Ken Wallace, Jacob Clear, Riley Fitzsimmons and Jordan Wood in the K4 1000m. The crew valiantly attempted to retain the London gold, but went down fighting in the final to finish fourth behind Germany, Slovakia and the Czech Republic.