Since his sporting career began in 1982, Berg-Knutsen is considered one of Norway's most prominent sport shooters, having achieved numerous successes in rifle shooting events at the ISSF World Championships, ISSF World Cup, and European Championships. He had also won a total of three medals at the ISSF World Championships, including two golds (1998 in Zaragoza, Spain, and 2006 in Zagreb, Croatia). One of the highlights of his career occurred at the 2006 ISSF World Shooting Championships, when he set a new world record of 1,181 points in the 300 m rifle three positions. Berg-Knutsen also competed for all rifle shooting events at the 2000 Summer Olympics in Sydney, and 2004 Summer Olympics in Athens, but he neither reached the final round, nor claimed an Olympic medal.