Schiffner made his international debut at an FIS race in Hinterzarten on February 23, 2008 and finished in 55th place. After further FIS races he made his debut in the Val di Fiemme in the Alpine Cup and finished 23rd straight away in the points. On January 17th, 2009 Schiffner made his debut in the FIS Cup in Lauscha and won 11 points straight away as 20th. After further FIS Cups, Alpine Cups, FIS races and junior competitions, he made his debut in the Continental Cup in Villach in July 2009 , but did not score any points as 49th and 40th. In the 2009/10 season, apart from the Continental Cup in Villach and Bischofshofen and the FIS Cup in Villach, where he came third, he only competed in the Alpine Cup. On July 2, 2010, Schiffner was the 25th to get COC points for the first time at the Continental Cup in Kranj . This season he started regularly in the Continental Cup for the first time, occasionally also in the FIS Cup and in the Alpine Cup. At the Junior World Championships in Otepää , Schiffner took 13th place in the individual and won the gold medal in a team with Michael Hayböck , Stefan Kraft and Thomas Lackner . His best Continental Cup result this season was a seventh place in Brotterode on February 5, 2011. Nevertheless, Schiffner was taken out of the Continental Cup after this competition and started in the last competitions in the FIS Cup and in the Alpine Cup. He won an FIS Cup in Ramsau and an Alpine Cup in Chaux-Neuve . He then established himself in the Continental Cup and won his first Continental Cup competition in Lillehammer in 2013. A year later he also won in Frenstadt. In the 2015 Summer Grand Prix, he took 4th place (with Michael Hayböck, Thomas Diethart and Andreas Kofler) in Hinterzarten. Immediately afterwards he made his best results so far in the Summer Grand Prix of Einsiedeln and Courchevel with a 16th and 13th place. In the 2015/16 season, Schiffner scored his first World Cup points in Engelberg.
Austria
Oslo
Frenštát
Engelberg
