A 2005 graduate of Kelly Walsh High School, Kristen lettered four years for coach Dean Hawks.

She was Big 12 Champion in both the 500 free (4:44.79) and 200 back (1:55.95) while also swimming the lead off leg for the record holding 800 freestyle relay.

Kristen was part of the Texas A&M's team which placed 4th at the NCAA Championships at Ohio State University.

Seven months after shoulder surgery, Heiss returned to the pool in July 2009 to compete in the World University Games in Belgrade, Serbia.

At the 2010 Big 12 Conference championship, Heiss won the 200 backstroke for the third time in her career in addition to winning the 500 freestyle.

Kristen finished her collegiate eligibility at the 2010 NCAA Championships where she placed 6th in both the 200 backstroke (1:53.67) and 500 freestyle (4:38.97).

After finishing her collegiate eligibility in March 2010, Heiss underwent a second shoulder surgery and retired from competitive swimming.

In July 2013, she was hired as an assistant swim coach at the University of Missouri, where she remained until the end of the 2015–2016 season.