Jesús David "Jesse" Vassallo Anadón[note 1] (born August 9, 1961) is a former competition swimmer and world record-holder in the 200 and 400 individual medley, who participated in the 1984 Summer Olympics for the United States.

[1] From 2004 to 2009, he served as the president of the Puerto Rican National Swimming Federation (Federación Puertorriqueña de Natación).

He began training with the Mission Viejo Nadadores under Hall of Fame Coach Mark Schubert, who would later become the coach of the USA Swimming Team, University of Texas Women, University of Southern California, and the American Olympic Team.

In 1978, Vassallo Anadón broke his first record in the 400-meter individual medley trials for the 1978 World Championships to be held in Berlin, Germany.

In 1979, Vassallo Anadón broke his third world record in the 200-meter individual medley and won gold in the 1979 Pan American Games, held in San Juan.

Also in 1979, he graduated from high school and was placed in the list of the top ten athletes in the world, along with Muhammad Ali, Mario Andretti and others by Sports Illustrated magazine.

[4] Vassallo Anadón was unable to attend the 1980 Summer Olympics held in Moscow, Russia, because of the U.S. and multinational boycott imposed by U.S. President Jimmy Carter as a response to the Soviet invasion of Afghanistan.

[1] Vassallo made better times in the 200- and 400-meter individual medley event at the competition than the two gold medalists in Moscow.

At the 1984 Summer Olympics in Los Angeles, he finished fourth in the finals of the 400-meter individual medley, and also competed in the 200-meter backstroke.

[10] In an interview for the Olympics Channel in 2018, Vassallo claims to have been a pioneer in the use of underwater dolphin kicks in backstroke events in 1976 when he was only 14 years old.