Greta Andersen was born on 1 May 1927 in Copenhagen, Denmark. She was married to John Sonnichsen, Andre Veress and Helge Jeppesen. She died on 6 February 2023 in Solvang, California, USA.
She won a gold medal in the 4x100 meter freestyle relay and a bronze medal in the 100 meter freestyle at the 1947 European Championships in Monaco. She won a gold medal in the 400 meter freestyle, a silver medal in the 4x100m freestyle relay, and a bronze medal in the 100 meter freestyle at the 1950 European Championships in Vienna.