Jessen was born in the Czech Republic and raised in New England before moving to Bethlehem. He competed in the 2016 and 2020 Olympics.
He scored 47th all-around in Rio and 57th all-around in Tokyo.
Now, he's a third-year student at Temple/St. Luke's School of Medicine in Bethlehem, Pennsylvania, and dreams of helping to heal other athletes like himself.
Watch the video above to hear his story in his own words.
To learn more about Temple/St. Luke's School of Medicine, visit their website.
8-year-old kidney donation recipient competes in Transplant Games
8-year-old kidney donation recipient competes in Transplant Games