Siegelaar rowed in the men's eight during the 2009, 2010 and 2011 World Championships finishing 3rd, 4th and 6th respectively, before competing at the 2012 Summer Olympics in London. In a close race Siegelaar finished 5th, only 0.5 seconds off the bronze medal. At the 2016 Summer Olympics in Rio de Janeiro he was part of the men's eight team that won a bronze medal.