She was multiple World and European champion, in both Long and Short Course Championships.

Her career began at the SC Dynamo Berlin in East Germany.

At the World Championships in 1994, her teammate Dagmar Hase qualified for the 200 metre freestyle final as the eight best swimmer, leaving Franziska only with the ninth best qualification time.

Therefore, Hase abandoned her start place and offered it to van Almsick, who then won the gold medal in the final bettering the world record.

In 1995, she was described by the New York Times as "the swimmer who united a nation", due to her status as "the first big star of German reunification".