Kendall Gretsch was born in Downers Grove, Illinois, with spina bifida. She played multiple sports as a child, including swimming, rock climbing, softball and basketball.

Gretsch became involved in triathlon after her sophomore year of college and won three consecutive world championships from 2014 to 2016. After her triathlon classification was not selected for Paralympic Games Rio 2016, Gretsch considered picking up a winter sport and settled on Para Nordic skiing.

Gretsch made her Paralympic debut as a winter-sport athlete, winning two gold medals in Nordic skiing at the Paralympic Winter Games PyeongChang 2018. Three years later, at the postponed Paralympics Tokyo 2020, she won gold in the women’s Paratriathlon, becoming just the fifth American to ever win gold at both the summer and winter Paralympic Games.