Walcker first became famous for the organ it built in the Paulskirche, Frankfurt, in 1833, which had 74 stops. Other important commissions followed rapidly, and Walcker became a pioneer of the "symphonic organ" style in Germany.
The largest Walcker organ in the world had 220 stops and over sixteen thousand pipes. It was built in 1930s for a state congress hall in Nuremberg and was destroyed by aerial bombings during World War II.