Grandin, who preferred hard courts, won three singles titles at ITF tournaments and 25 doubles titles with changing partners. She was trained by Petra de Jong.
On September 25, 2011, she won her only title on the WTA Tour at the side of Vladimíra Uhlířová . With her she also reached the semifinals at the WTA tournament in Charleston in 2012 . On May 14, 2012, she recorded her best position in the WTA world rankings in doubles with 22nd place . She ended her career in January 2015.