In 2008, Nagasu became the youngest woman since Tara Lipinski in 1997 to win the U.S. senior ladies' title, and the second-youngest in history at the time. She is the first lady since Joan Tozzer in 1937 and 1938 to win the junior and senior national titles in consecutive years. Nagasu represented the United States at the 2010 Winter Olympics at the age of 16 and placed 4th in the ladies' event. In 2017, she landed the difficult triple Axel jump for the first time in international competition at the 2017 CS U.S. Classic. During her free skate in the team event at the 2018 Olympics, she became the first American ladies' singles skater to land a triple Axel at the Olympics, and the third woman from any country to do so. This also made her the first senior ladies skater ever to land eight triple jumps (the maximum allowed in the free skate under the Zayak rule) cleanly in international competition.