The instrument evolved from Rhodes's attempt to manufacture pianos while teaching recovering soldiers during World War II.

CBS oversaw mass production of the Rhodes piano in the 1970s, and it was used extensively through the decade, particularly in jazz, pop, and soul music, as well by many rock artists.

Pressing a key results in a hammer striking a thin metal rod called a tine connected to a larger "tone bar".

[3] Simply hitting tines does not need an external power supply, and a Rhodes will make sound even when not plugged into an amplifier,[4] though like an unplugged electric guitar, the volume level and tone will be diminished.

[5] The Suitcase model Rhodes includes a built-in power amplifier and a tremolo feature that bounces the output signal from the piano across two speakers.

The Rhodes has a better sustain, while the Wurlitzer produces significant harmonics when the keys are played hard, giving it a "bite".

[8][9] According to Benjamin Love of Retro Rentals, an equalization spectrum analysis of the instrument will have a gap where the frequency of a lead vocal can be.

He designed a method that combined classical and jazz music, which became popular across the United States,[10] and led to an hour-long nationally syndicated radio show.

[2] By 1942, Rhodes was in the Army Air Corps, where he created a piano teaching method to provide therapy for soldiers recovering from combat in hospital.

The [aluminum] xylophone bars are made from discarded hydraulic systems, the plywood from hatchways, keys from the fuselage spruce, and hammers from the hardwood of the propellor.”[14] On 18 March 1945 Rhodes visited the Santa Ana (CA) Army Base Convalescent Hospital, bringing with him eight Xylettes, and having visited seven similar military hospitals across the U.S.[15] When Rhodes had visited the Army's Fort Logan (CO) convalescent hospital a month earlier, he supervised construction of Xylettes and provided instruction, noting that "exercise afforded by a keyboard instrument is effective in the restoration of neuro-muscular coordination of fingers, hands and arms.”[16] A Popular Mechanics article in June 1945 pictured recovering veterans playing their Xylettes at the Army’s Ft. Thomas (KY) convalescent hospital.

Rhodes, in California, next developed an electrically-amplified 38-key instrument, again without strings—instead, using carbon steel rods and advertised as "never needing to be tuned."

[24] By mid-1948 the Pre-Piano was being used for teaching in the Los Angeles Public School System,[25] and was eventually adopted in other cities, including Chicago.

Among Rhodes's promotional appearances away from Los Angeles was Chicago's Lyon & Healy music store, where he demonstrated the instrument on July 21-22-23, 1948.

[26] During the summer of 1948 pianist and song-stylist Gwen Bari was Rhodes's representative and demonstrator in Philadelphia,[27]—including a local television broadcast.

[33] The instrument introduced the design that would become common to subsequent Rhodes pianos, with the same Tolex body as Fender amplifiers and a fiberglass top.

Actual production (for retail sale) in Fender's Fullerton plant, however, began early in 1962—following manufacture of prototypes that "[had then] been in use throughout the Southwest for more than a year.”[34] The earliest-known national advertisement for the instrument was in Down Beat's July 1962 issue.

In 1976, the company posted an advertisement claiming that of the top 100 Billboard albums featuring electric pianos, 82% of them used a Rhodes.

[43] The Rhodes Mk III EK-10 was a combination electric piano and synthesizer, introduced in 1980 before CBS bought ARP Instruments in 1981.

The instrument was unreliable with a problematic production, particularly when a shipment of 150 units to Japan caused interference with local television reception.

[43] Rhodes pianos produced under the original run had an inconsistent quality as the company wanted to mass-produce the instrument.

[40] It included a lever that moved the relative position of the tines to the pickups, modifying the sound, and fed the output signal through additional electronics.

[10] In 2007, his former business partner Joe Brandstetter acquired the rights to the name and re-formed Rhodes Music Corporation.

[48] The company introduced a reproduction of the original electric piano, the Rhodes Mark 7, housed in a molded plexiglass enclosure.

[64] Donny Hathaway regularly used the Rhodes; his hit single, "This Christmas", which receives seasonal radio play on African American stations, makes a prominent use of the instrument.

[70] German pianist and composer Nils Frahm uses a Rhodes piano extensively in his studio and live performances.