Thomas ran track and played basketball in high school in Philadelphia exceling in hurdles, high jump and long jump. She began playing rugby her freshman year at University of Central Florida and was selected to the Women's Collegiate All-Americans' tours in 2013 and 2014 in France and Canada.
Thomas made her World Rugby Sevens Series debut in São Paulo, Brazil in February 2015, beginning one of the most prolific sevens career in USA Rugby history. Continuing to make appearances on the sevens scene, Thomas would earn her first XVs cap two at the 2017 CanAm Series. That same year, she suited up for the 2017 Rugby World Cup, where the Eagles soared to a fourth place finish.
Ultimately converting back to the sevens pitch, Kris has become a leader in the sevens clubhouse and was selected to the Tokyo 2020 Olympic games roster.