Weiss started his international career in 2005 in FIS races . From January 2007 he started in the B-World Cup of Nordic Combined. At the Junior World Championships 2007 in Tarvisio , he won the gold medal with the team in the team competition. A year later at the Junior World Championship in Zakopane in 2008 he won silver with the team. In 2009 in Štrbské Pleso , the team narrowly missed the medal ranks with fourth place. On February 14, 2009 he made his debut in the Nordic Combined World Cup for two races . In the second World Cup in Klingenthal , he achieved the points for the first time with 28th place. Having won three World Cup points, he finished the 2008/09 season tied with Marjan Jelenko in 74th place in the overall World Cup ranking. Since then he has continued to compete in the Continental Cup and has already achieved several placements among the top ten.