Buschmann described his new instrument to his brother as "a new instrument that is truly remarkable. In its entirety it measures but four inches in diameter...but gives me twenty-one notes, and all the pianissimos and crescendos one could want without a keyboard, harmonies of six tones, and the ability to hold a note as long as one would wish to." Initial designs by Buschmann were widely imitated, leading to many modifications and advancements. A Bohemian instrument maker named Richter may have made the most important advancements in early harmonica design. Around 1826, he developed a variation that consisted of ten holes and twenty reeds, with separate blow and draw reed plates mounted on either side of a cedar comb. Richter's tuning, utilizing a diatonic scale, became the standard configuration of what Europeans referred to as the Mundharmonika or mouth organ.

In 1857, the history of the harmonica changed dramatically as German clock maker Matthias Hohner turned to manufacturing harmonicas full-time. With the help of his family and a hired workman, he was able to produce 650 instruments that year. Soon after, he added local workers and developed mass production techniques. Young Hohner was an outstanding businessman and showed his marketing savvy by developing ornate cover plates bearing the producer's name.

He introduced the harmonica to North America in 1862, a move which would propel the Hohner company to its status as world leader in harmonicas. By 1887, Hohner was producing more than one million harmonicas annually. Today, Hohner produces over 90 different models of harmonica, with a variety of styles and tunings which allows the player freedom of expression in all forms of music, from Classical and Jazz to Blues, Country and Rock, to the indigenous music of people worldwide.