Infiniti's 5 Series rival
Initially, it will be powered by a 3.7 V6 petrol engine, but a 3.0-litre V6 diesel will follow just a month later.
A petrol-electric hybrid, with a 3.5-litre V6 engine and an electric motor, is expected by February 2011.
The M Series is a front-engined, rear-wheel-drive saloon that can be ordered with an updated version of Infiniti's four-wheel-steering system.
All models come with a seven-speed automatic gearbox and Infiniti's Drive system, which allows the driver to switch between four set-ups: Sport, Eco, Standard and Snow.
Switching modes adjusts the transmission and engine mapping, and the responses from the four-wheel-steering system.
The M Series will have what Infiniti says is a world-first safety feature – a blind-spot intervention system that will pull the car back into its lane if it detects a car approaching in the blind spot.
The car will get its European debut at the Geneva motor show next month.