At the 1956 and 1957 Oscars, James Dean was nominated for his performances in East of Eden and Giant respectively, he didn't win the awards ultimately.
After James Dean popularized them in the movie, Rebel Without a Cause, wearing blue jeans by teenagers and young adults became a symbol of youth rebellion during the 1950s.
Besides the self-destructive tendencies, besides his philosophizing about sudden death followed by immortality, James Dean was serious about his craft and development as a professional actor.