Gibson had made forays into radical body shapes - the Flying V and Explorer) in the 1950s - but they failed. The president of Gibson, Ted McCarty, hired car designer Ray Dietrich to design a guitar that would have popular appeal. Under Dietrich, the Firebird took on the lines of mid-50s car tailfins. Dietrich took the Explorer design and rounded the edges. The most unusual aspect is that the guitar is "backward" in that the right-hand (treble) horn of the body is longer than the other. Thus, the original Firebirds were unofficially referred to as "reverse".
The Firebird is the first Gibson solid-body to use neck-through construction, wherein the neck extended to the tail end of the body. The neck itself is made up of five plies of mahogany interspersed with four narrow strips of walnut for added strength. Other features were reverse headstock (with the tuners on the treble side) and "banjo" tuning keys, as well as mini-humbucking pickups. These were not identical to Epiphone mini-humbuckers, having an alnico bar magnet polepiece in each coil. In contrast, the Epiphone design is a mini-PAF, with a single alnico bar magnet at the pickup's base and six iron polepieces per coil. Some Firebirds from 1965 featured Gibson's single-coil P-90 pickup.
The Firebird line went on sale in mid-1963 with four models distinguished by pickup and tailpiece configurations (see below). Unlike the Les Paul and SG line, which used the terms "Junior", "Special", "Standard" and "Custom", the Firebird used the Roman numerals "I", "III" , "V" and "VII". Gibson's line of Thunderbird basses is rooted in the design of the Firebird, and uses even Roman numerals to distinguish it. From 1965 to 1969, Gibson introduced "non-reverse" models after failing to achieve marketing success with the unusual reverse-body design. Gibson had also received complaints from Fender that the Firebird headstock mirrored the Stratocaster and that the body violated Fender's design patents, with Fender threatening a lawsuit. The "non-reverse" body is a more standard double-cutaway design, with the bass horn being longer than the treble horn and the headstock having the tuners mounted on the bass side. It also had a standard glued-in ("set") neck rather than neck-through construction, as well as other, less noticeable changes in design and build. Pickup and tailpiece configuration for the V and VII were the same as the earlier "reverse" models, although the I- and III-models were now shipped with two or three P-90 pickups and plain vibratos. After a few years of disappointing sales, the "non-reverse" line was dropped. "Reverse" body Firebirds were first reissued from 1972-1979, with a commemorative "Bicentennial" model released in 1976.