Malcolm started sailing for Manly Juniors at Hunters Hill Sailing Club when he was 8 years old.

Malcolm narrowly missed selection for the Sydney 2000 Olympics but went on to win the 2004 world championship with skipper Nathan Wilmont. They were selected for the Athens 2004 Olympics where they finished 12th.  

The pair went on to win world titles in 2005, 2006 and 2007 in the 470 class.

At the Beijing 2008 Olympics, Malcolm won gold in the 470 class along with Nathan. At the following London 2012 Olympics, he won gold a second time with Matt Bleacher. Malcolm became the first Australian to successfully defend a gold medal and was the only Australian athlete at the London games to defend a title, this feat earnt him the honour of being the Australian flag bearer at the closing ceremony. 

Between 2005 to 2012 Malcolm captained the Australian sailing team and won a total of 7 world 470 class titles.

His other honours and achievements include:

• 2005, 2007 and 2008 Australian Institute of Sport Team of the Year
• 2008 and 2012 Australian Yachtsman of the Year
• 2009 Medal of the Order of Australia (OAM) for his services to sailing
• 2011 inducted into the Australian Institute of Sport ‘Best of the Best’
• 2015 Australian Chef de Mission to the Pacific Games
• 2016 inducted into the Sport Australia Hall of Fame
• 2020 inducted into the Australian Sailing Hall of Fame

Malcolm lives on the Northern Beaches and still enjoys sailing including competing in the 16ft skiff fleet that sails out of the Manly 16ft skiff Sailing Club.