Katja Wirth is the sister of the former ski racer Patrick Wirth , who also brought her to alpine ski racing. After successfully taking part in many children's races at a young age, she decided to go to the ski school in Stams (Tyrol) after graduating from primary school . Thanks to the support there, Wirth took part in FIS races at an early stage , and this was also where her great talent was shown. In 1997 she suffered a torn cruciate ligament , but was later able to return to the ÖSV squad.
After she competed for the first time in all races for the A-squad of the ÖSV in the World Cup in the 2005/06 season , she qualified for two permanent positions in the Downhill and Super G World Cup. She achieved her best World Cup result on March 1, 2003 in Innsbruck when she finished second in the downhill race. She also won the European Cup in Downhill (2003) and twice in Super-G (2002, 2006). On December 11, 2007, she announced her resignation.