Sebastian Smythe is a fictional character from the television series Glee. He is portrayed by actor Grant Gustin and first appears in the show's fourth season. Sebastian is a member of the Dalton Academy Warblers, a competitive a cappella group, and is known for his charming personality and strong vocal abilities. In the series, Sebastian often serves as a rival to the main characters, particularly Kurt Hummel and Blain Anderson. His character is depicted as confident and somewhat manipulative, which adds tension to the storyline. Despite his antagonistic role, he also showcases moments of vulnerability throughout the series.