He was famous as a musician during his lifetime because he was talented.
pooing
Most all of his life (1685-1750)
bach was famous for his compositions.
Bach was a noted organist during his time, but also played harpsichord and violin.
Composer.
Carl Philip Emanual Bach (CPE Bach) and Wilhelm Friedmann Bach were Bach's famous sons. Both were also composers.
During the composer's life it was likely Haydn. Looking back at all time its probably Mozart or Beethoven. Johann Sebastian Bach & Wolfgang Amadeus Mozart.
He's not Bach is.
Bach's most famous song is Toccata and Fugue in D Minor.
Bach was most famous as an organist.
Bach's notable Toccata and Fugue was written during the Baroque era, as was Handel's famous Water Music Suite.
The Golden variations were written 9 years before JS Bach's death.