Kasslatter achieved his first international successes in the Intercontinental Cup. In the 1997/1998 season she reached third place overall and in the 2001/2002 and 2002/2003 seasons she won the overall ranking. At the 2000 European Junior Championships in Umhausen , she was eighth. At the end of January 2002 Kasslatter competed in Hüttau and Železniki her first World Cup races , which she finished in seventh and fifth place. A little later she started at the European Championships in Frantschach for the first time in a title fight in the general class and took eleventh place at the same time with the Austrian Anna Braun .
In the winter of 2002/2003 , Kasslatter could not qualify for any World Cup races within the strong Italian team. She only succeeded in doing this again for the first race of the 2003/2004 season , which she then surprisingly won. She confirmed this performance with two second places in the next two races and with another two top 5 results, she achieved second place in the overall World Cup behind Russian Ekaterina Lavrentieva , who celebrated four victories of the season. At the 2004 European Championship in Hüttau, however, she only finished eighth. In 2004, the South Tyrolean became the Italian single-seater champion for the first time. She won this title three more times in 2005, 2007 and 2009. In the 2004/2005 season , Kasslatter was among the top six in all World Cup races and made it onto the podium twice. She was third in Unterammergau and second at the season finale in Olang , which she finished fourth in the overall World Cup. At her first world championship in January 2005 in Latsch , she achieved fifth place.
In October 2005 Kasslatter gave birth to a daughter. She therefore did not take part in any competitions in winter 2005/2006. In the 2006/2007 season she returned to the World Cup and celebrated the second World Cup victory of her career in the fourth race of the season in Umhausen . She referred the Russian Ekaterina Lavrentjewa to second place, who had previously won eleven World Cup races in a row. With another podium place in Campill , Kasslatter achieved third place in the overall World Cup behind Lawrentjewa and her team colleague Renate Gietl . At the 2007 World Championships in Grande Prairie , she was sixth.
In the 2007/2008 season , Kasslatter only finished third in the World Cup once on the podium in Umhausen. She finished the other races in fourth or fifth position and in the overall World Cup she finished fourth. She celebrated her greatest success at the 2008 European Championships in Olang, where she won the silver medal behind Lavrentieva. In the 2008/2009 World Cup season , Kasslatter remained without a podium. She achieved two fourth, three fifth and one seventh place and thus fifth place in the overall ranking. She celebrated the last highlight of her career at the 2009 World Championships in Moos in Passeier , when she won the bronze medal behind Renate Gietl and Jekaterina Lavrentjewa. Kasslatter then announced that she would end her career after the World Cup final. This decision was made before the season started.