Taejun Sun was born in Seoul (South Korea) and studied singing at the Seoul National University and at the Cologne University of Music and Dance. He was then a member of the International Opera Studio of the Cologne Opera for two years before becoming an ensemble member at the Deutsches Nationaltheater Weimar, where he continues to perform to this day.

Guest engagements have taken Taejun to the Seoul Metropolitan Opera, the Cologne Opera, the Goethe Theater Bad Lauchstädt, the Braunschweig State Theater, the Saxony State Theater, the Coburg State Theater, the Solingen Theater, the Winterthur Theater, L'arte del mondo, and the Wuppertal Symphony Orchestra.

His repertoire includes a wide variety of tenor roles, with a special focus and affinity towards belcanto.