When she was growing up Sirpa Ylönen began to compete in rifle shooting, and she went on to become one of the best female sports shooters in Finland. In the 1980s Ylönen won six individual Finnish titles along with a team title. In 1982 she won gold in the 50 metres small-bore rifle prone event at the World Shooting Championships in Caracas. Two years later she competed in the 10 metres air rifle and the 50 metres small-bore rifle three positions at the 1984 Los Angeles Olympics, finishing 8th and 12th, respectively. In 1986 Ylönen won another gold at the World Championships, this time in the 10 metres team air rifle, before competing at the 1988 Seoul Olympics. Away from sport Ylönen helped to create green spaces in her hometown of Mikkeli and was a member of the Finnish Landscape Designers Association.