Born in Seoul, South Korea, Hee Seo began her ballet training in her hometown at the Sun-hwa Arts Middle School. She was awarded a three-year full scholarship to continue her training at the Universal Ballet Academy in Washington, D. C. In 2003, Seo won a scholarship to train at the John Cranko Ballet Academy in Stuttgart. She is the recipient of the 2003 Prix de Lausanne Award and the 2003 Grand Prix at the Youth American Grand Prix in New York.
Seo joined the ABT Studio Company in 2004 and the main Company as an apprentice in May 2005 and the corps de ballet in March 2006. Her repertoire with the Company includes Polyhymnia in Apollo, Nikiya, Gamzatti, the Lead D'Jampe and a Shade in La Bayadère, Cinderella in Frederick Ashton's Cinderella, Twig in James Kudelka's Cinderella, Prayer in Coppélia, Mercedes and a flower girl in Don Quixote, the Glove Seller in Gaîté Parisienne, Giselle and Zulma in Giselle, Olympia in Lady of the Camellias, The Moor's Wife in The Moor's Pavane, Natalia Petrovna in A Month in the Country, Clara, the Princess and one of the Nutcracker's Sisters in Alexei Ratmansky's The Nutcracker, Natalia in On the Dnieper, Tatiana in Onegin, Juliet in Romeo and Juliet, Princess Aurora, the Lilac Fairy, the Fairy of Sincerity and Princess Florine in The Sleeping Beauty, Odette-Odile, the pas de trois, the Polish Princess and a big swan in Swan Lake, the Sylph in La Sylphide, the Prelude in Les Sylphides, Ceres in Sylvia, Thaïs Pas de Deux and roles in Ballo della Regina, Birthday Offering, The Brahms-Haydn Variations, Chamber Symphony, Dark Elegies, Drink to Me Only With Thine Eyes, Duets, From Here On Out, The Leaves Are Fading, Overgrown Path, Raymonda Divertissements, Seven Sonatas and Thirteen Diversions. She created a leading role in With a Chance of Rain.
Seo was appointed a Soloist in August 2010 and a Principal Dancer in July 2012.
Ms. Seo's performances with American Ballet Theatre are sponsored by Pamela and David B. Ford.