Harptone traces its origins to 1886 in Newark, New Jersey, beginning as Maulbetsch and Whittemore, later becoming The Felsberg Company, and adopting the Harptone name by 1929. The company built its reputation as one of America's earliest and most prolific manufacturers of instrument cases, supplying protective cases used by guitar makers including C.F. Martin, D'Angelico, Epiphone, Gibson, Gretsch, and Guild from the 1920s through the 1960s.

In the mid-1960s, under owner Sonny Brooks and with luthier Sam Koontz overseeing design, Harptone expanded into building acoustic and electric guitars. From 1966 through the mid-1970s, the company produced guitars under the Harptone, Standel, and Supreme names, with models such as the L6, the Lark L12-NC 12-string, and the E-6 archtop. A signature trait of Harptone acoustics was their arch-back construction, which gave them a distinctive resonance compared to flat-back competitors. Sam Koontz left in 1972, electric production wound down by 1969, and the brand was sold to Diamond S in 1975 before guitar manufacturing ended in 1980. Total production is estimated at roughly 5,000 to 7,000 instruments, and surviving examples are sought after by vintage collectors.

The Harptone case line was later revived by TKL Products Corp. of Oilville, Virginia, which produces cases by hand at its Cedar Creek Custom Case Shoppe. The reintroduced Historic Series recreates vintage case designs from the 1940s, 1950s, and 1960s, and the brand also offers modern lines such as the Redline and Classic series for dreadnought, OM, and small-body acoustics, along with cases for electric guitars and mandolins.

Harptone has 2 products cataloged on Equipboard, including Steel-string Acoustic Guitars. Their gear is featured by 2 artists, with the strongest followings in Rock, Pop, and Funk / Soul. Notable users include George Harrison and David Bowie.