Jaesig Lee was born in Jinju (South Korea). He began his vocal studies in 1997 under Sungil Ha at the  Jinju Mechanical Technology High School. From 2000–2005 he continued his education at the  Korean National University of the  Arts in Seoul (class of Gwangsun Song). In 2003 he took classes from Stoyan Popov in Sofia. He has performed the  role of Alfred (Die Fledermaus) at the  Seoul Arts Center and appeared in a gala concert at the  Burgas Opera House (Bulgaria), a concert at the  Musical Olympus festival at the  Mariinsky Theatre, a Maria Callas memorial concert in Athe ns, the  Maria Callas Grand Prix International Competition prize-winners’ concert and The Six Rising Stars gala concert at Carnegie Hall in New York in addition to numerous concerts in Korea. In January 2011 he performed at the  gala presentation of the  Musical Olympus festival at the  Esplanade Concert Hall in Singapore.
In 2008 Jaesig Lee took part in three singing competitions in South Korea at which he won the  Grand Prix and 1^st and 2^nd prizes. His next successes came with the  Grand Prix at the  Maria Callas Grand Prix International Competition in Athe ns (2009) and 2^nd prize at the  Marseille International Opera Competition (2009). In the  summer of 2010 Jaesig Lee won 1^st prize at the  Wilhelm Stenhammar International Singing Competition in Sweden and in December 2010 he won the  1^st prize at the  Giovanni Batista Viotti International Competition in Parma.