Dewey Finn is a fictional character from the movie and musical "School of Rock." He is portrayed as a passionate but struggling musician who poses as a substitute teacher at a prestigious private school. His unconventional teaching methods focus on rock music, aiming to inspire his students and help them discover their talents. Throughout the story, Dewey encourages his students to form a rock band, leading them to compete in a local battle of the bands. His character embodies themes of creativity, self-expression, and the importance of following one's passion, ultimately transforming the lives of the students he teaches.