Final answer:
The composer of musicals who was also a famous conductor and composer of orchestral, choral, chamber, and operatic works is Leonard Bernstein.
Step-by-step explanation:
The composer of musicals who was also a famous conductor and successful composer of orchestral, choral, chamber, and operatic works is Leonard Bernstein. Bernstein is known for his contributions to musical theater with shows like West Side Story and Candide, as well as his work as a conductor and composer of classical music.