Although Hilkka Riihivuori was one of the best female cross-country skiers in the 1970s, she never won an individual gold medal at a major championship. She made her international début at the 1972 Olympic Games, where she won a silver in the relay and was fifth at 5 km and eighth in the 10 km. The 1974 World Championships were not kind to Riihivuori, as her best place was fourth in the relay at those championships, but in 1974 she won the 10K at the Holmenkollen Ski Festival. She would win two more times at Holmenkollen (1977 in the 5 km and 1980 in the 10 km) and would be awarded the Holmenkollen Medal in 1977. At the 1976 Olympics, Riihivuori again won silver in the relay, while placing fourth in the 5 km and ninth in the 10 km. The 1978 World Championships were probably her best major competition, winning her only major championship gold (in the relay) and her first individual medals (silver in the 5 km and bronze at 10 km). She was also fourth in the 20 km at the 1978 World Championships. At the 1980 Winter Olympics, Riihivuori won her third and fourth Olympic medals, again silvers, but this time individual ones in the 5 and 10K, while placing fifth in the relay. Riihivuori made her last international appearance at the 1982 World Championships, where she again won silvers in both the 5 and 10 km, bronze in the 20 km, and was fourth with the relay team. Riihivuori was selected as the Finnish Female Athlete of the Year consecutively from 1980-82. After her sporting career ended she worked as a sports instructor.