He achieved his first international successes in 1998 and 1999, when he became Junior World Champion with the Austrian team. After his first appearances in the Ski Jumping World Cup he was able to show for the first time in the 2001/02 season and with his first podium in Engelberg he also qualified for the 2002 Winter Olympics in Salt Lake City . After three less successful years, he fought his way back into the Austrian team and became a member of the national team of the ÖSV together with Thomas Morgenstern , Andreas Kofler and Andreas Widhölzl team Olympic champion at the 2006 Winter Olympics in Turin . At the Ski Flying World Championships 2008 in Oberstdorf, Koch was vice world champion in individual and team world champion with the Austrian team. He also won the world championship title with the Austrian team at the 2010 ski flying world championships. When ski flying in Harrachov on January 8, 2011, Koch won his first World Cup victory in front of his compatriot Thomas Morgenstern. On March 11, 2012 he won his first jumping on a large hill after three victories in ski flying on Holmenkollbakken in Oslo, Norway . In April 2012 he announced that he would continue his career for at least one more season, although he had previously struggled with back problems several times.
He ended his active ski jumping career with a farewell jump on March 22, 2014 at the World Cup finals in Planica, Slovenia . After the end of his career, Koch was hired as a co-commentator by ORF .
Landesschiverband and Kleine Zeitung (ed.): From Großglockner to Klammer-Stich - 100 years of skiing in Carinthia . Pp. 86–89, Martin Koch: Just me and the ski jump and a great day, Carinthia Verlag 2007, ISBN 978-3-85378-622-2 .