As a student at Queen Charlotte College in Picton, Sullivan competed at the 2003, 2004 and 2005 national secondary school rowing championships (Maadi Cup).

[6] At the 2012 Summer Olympics at Eton Dorney, Windsor, Sullivan and rowing partner Nathan Cohen won the gold medal in the men's double scull event.

[5] They finished ahead of the Italy's Alessio Sartori and Romano Battisti by 1:13 seconds, and Slovenian 2000 Olympic champions and 2004 silver medalists Luka Špik and Iztok Čop came in third.

[14] In June 2014, Sullivan announced he was retiring from rowing in order to pursue a career with the New Zealand Fire Service as a firefighter based in Auckland.

[15] In 2016, Sullivan joined Emirates Team New Zealand,[4] as a grinder a (i.e. spinning the handles that produce hydraulic pressure to move the boat's wings and daggerboards), for the 2017 America's Cup in Bermuda.