Cori Thiermann attended Cedarburg High School from 1997-2001. Thiermann was an outstanding softball player, starting all four years and being named to the All-State Team as a senior and the All-Conference Team all four years. Thiermann helped lead her team to the North Shore title and took her team to the State Tournament twice. She compiled a 76-15 record over her four years and was part of a State-ranked team her last three seasons. She is also the record holder for most doubles in a career with 19 from the cleanup position and was team Captain her senior year. Thiermann was regarded as an all-around player as she called the game from behind the plate, and opposing players rarely opted to steal on her.

Thiermann earned a Division I scholarship to UW-GB where she played all four years. She was a 4-year Horizon League Honor Roll member, Horizon League Champion and a 4-year All-Conference selection. Thiermann began her coaching career at Berry College in Georgia where she instituted its softball program in 2009. She has accumulated five Conference Coach of the Year awards and was a part of a 17-0 season since the 2009 inaugural season.