Weiss started his career with FIS races and in the European Cup , from 1991 he also started in the World Cup . He scored his first World Cup points on March 22, 1992 in Crans-Montana when he finished 17th. On December 20, 1993, he was sixth in Madonna di Campiglio - a result that would remain unsurpassed for more than five years - at the 1994 Winter Olympics in Lillehammer eighth.
But then the thread broke and Weiss quickly lost touch with the world's best, which was mainly due to the many failures. For example, in 1995 he did not finish seven times in a row. He only started sporadically in the World Cup and the coaches downgraded him. It was not until the end of 1998 that it was able to stabilize again. He celebrated his greatest success on January 9, 2000, when he surprisingly won the World Cup slalom in Chamonix . After failing to qualify for the 2002 Winter Olympics, he resigned from top-class sport.