Kleinrath, who starts for WSV Sparkasse Bad Ischl and lives in Altmünster , was able to sniff international competition air at the FIS Schoolchildren Grand Prix 2015 in Ruhpolding at the age of eleven . The young athlete competed in the ski jumping competition as the Austrian representative of the “Schoolgirls 12” age group and barely missed the podium as fourth. She made her debut in the Nordic Combined Alpine Cup and in the Alpine Ski Jumping Cup on March 4, 2017 in Hinterzarten , where she directly reached the top 10 in both disciplines. For the first time she jumped on the podium at the ski jump in Klingenthal at the beginning of August 2019 .
A few weeks later, Kleinrath made his debut in the Grand Prix . Together with Lukas Klapfer , she finished eighth in the mixed team competition in Oberwiesenthal in the Austria II team. The 15-year-old also performed well in the individual races, so that she finished eleventh in the overall Grand Prix standings. In October Kleinrath won the bronze medal behind Lisa Hirner and Johanna Bassani at the first Austrian state championship in Nordic combined . When she made her debut in the Continental Cup at the end of January 2020, Kleinrath immediately finished fifth in the top ten. The next day she led the competition after jumping and finally took third place. At the Nordic Junior Ski World Championships 2020 in Oberwiesenthal, Kleinrath ran to twelfth place in the Gundersen singles, before she just missed the medal ranks in mixed team competition as fourth together with Johannes Lamparter , Lisa Hirner and Manuel Einkemmer .