Shortly before the Nordic World Ski Championships in 1982 in Oslo , Norway , Karvonen took part in a World Cup competition for the first time in Reit im Winkl . Over the 15-kilometer distance, he was able to take 15th place. Then he was nominated for the world championship, where he reached 10th place over the 30 kilometers freestyle and 14th place over the 15 kilometers freestyle. These results secured him a place in the Finnish relay, which won the bronze medal at the same time as the GDR relay . Two years later at the 1984 Winter Olympics in Sarajevo , he again won the bronze medal with the Finnish relay. But Karvonen was also able to decorate himself with medals in the individual competitions. Over 15 kilometers classic he won the silver medal behind Gunde Svan and over 50 kilometers classic behind Thomas Wassberg and Svan the bronze medal. As fifth in the 30 kilometer freestyle, he just missed another medal. Since the competitions in Sarajevo were also counted as part of the World Cup, Karvonen was able to book his best place in the overall ranking of the World Cup with eleventh place at the end of the 1983/84 season.
At the Nordic World Ski Championships in 1985 , Karvonen was the first to go to a major event without a medal. Over 30 kilometers classic he came sixth, over 15 kilometers classic twelfth and with the Finnish relay he was fourth. Two years later at the Nordic World Ski Championships in Oberstdorf in 1987 , he again won a silver medal over 30 kilometers behind Wassberg. Karvonen was unable to repeat the successes of previous years at the 1988 Winter Olympics in Calgary . Over 15 kilometers classic he was only 20th and over the double distance only 19th, whereupon he was not nominated for the relay competition for the first time. Karvonen also competed at the Nordic World Ski Championships in 1989 in his native Lahti and just missed his fourth individual medal in a major event when his compatriot Harri Kirvesniemi won over 15 kilometers. In the relay competition Karvonen almost celebrated his first world title, but the Finnish team had to admit defeat to the Swedish relay by a second. After the World Cup, Karvonen ended his international career.