The Isotta Fraschini Tipo 6 Competizione, which will be raced in partnership with the British Vector Sport team, was unveiled on Tuesday at the Automobile Club Milano.
The reveal of the car developed by Michelotto Engineering means the marque has met its stated target of completing the car by the end of February.
Isotta director of motorsport Claudio Berro said: "Today, we are exactly where we predicted four months ago when we announced that Isotta Fraschini would be back and that it would do so, according to tradition, with a racing car.
"The Tipo 6 LMH Competizione is now in its complete and real configuration, and the intention for the 2023 season remains to compete in the WEC on a race-by-race basis as soon as the car is homologated by the FIA.
"In the meantime, we will be grinding kilometres together with Vector Sport to be ready as soon as possible."
A plan to give the Tipo 6 Competizione a debut on home ground at the Monza WEC round in early July was outlined by Berro to Autosport earlier this year.
The latest LMH is powered by a twin-turbo three-litre V6 developed for Isotta by HWA Engineering in Germany and a front-axle hybrid system supplied by Bosch.
The aerodynamics have been developed by WAE Technologies and the chassis and bodywork produced by ARS Technologies, a leading composite company in Italy.
Isotta has also laid out a blueprint to become a legitimate automotive manufacturer.
The Competizione will be one of three versions of the Tipo 6: there will also be a track-day version of the car known as the Pista and a road car to be called the Strada.
Customer versions of the LMH will also be made available.
Isotta president Alessandro Fassini, a former World Rally Championship driver, announced a €100 million (£88 million) investment in the Isotta brand at the launch, as well as plans to build a total of 50 Tipo 6s over a five-year period.
A new two-seater super-sportscar is also under development by Isotta for 2026.
