In 1999 Steffen won six titles at the European junior championships, and won a medal as a member of Germany's freestyle relay team at the Summer Olympics 2000. In 2004, she asked to swim the 4×100 m relay. But after the Olympics, she took one year off swimming and concentrated on her studies, which were not finished.
At the Championships in Budapest on 2 August 2006, Steffen clocked 53.30 in the women's 100 m freestyle event, breaking the world record and upstaging the previous record of 53.42 set by Libby Lenton of Australia. Even though Libby swam a time of 52.99 on 4 April 2007 during the mixed 400 metre freestyle relay, this time was not recognized by the FINA as world record, because the race is not considered to be a FINA event.
At the same championships, Steffen was part of two world record-breaking relay teams. First, the German 4×100 m women's relay team of Dallmann, Goetz, Steffen and Liebs took the Australian 4×100 m freestyle relay (Mills, Lenton, Thomas and Henry) world record of 3:35.94, clocking a time of 3:35.22. The German women's relay team of Dallman, Samulski, Steffen and Liebs, then swam a time of 7:50.82 to take the previous US 4×200 m freestyle relay (Coughlin, Piper, Vollmer and Sandeno) world record that stood at 7:53.42. She had recently participated in the FINA World Championships in Melbourne where she finished third in the 100 metre freestyle event and second in the 4×200 metre freestyle relay.
During the 2008 Summer Olympic Games in Beijing, China, Steffen won the 100-meter freestyle, catching world record-holder Libby Trickett of Australia at the last stroke. Steffen touched in 53.12 seconds, bettering her own Olympic record of 53.38 set on the leadoff leg of the 4×100 m freestyle relay. Steffen then edged out Dara Torres to win the 50-meter freestyle gold with a time of 24.06 seconds, winning by 0.01 seconds.
At the World Championships in Rome on 31 July 2009, Steffen clocked 52.07 in the women's 100 m freestyle event, breaking the world record and upstaging the previous record of 52.22 set by herself four days before.. Two days later on 2 August 2009, Steffen won her second title in the women's 50 m freestyle event, breaking the world record with a time of 23.73 seconds.
Women Athletes for Swimming