The line-up, unveiled at the North American International Motor Show in Detroit, includes the first full-hybrid IS, the IS 300h, together with the petrol-powered IS 250.
Both versions feature rear-wheel drive and will be available with a further evolution of Lexus' F Sport package.
Acknowledging that driving performance is the prime consideration for sports saloon customers, Lexus says it has engineered the new IS to deliver outstanding dynamic performance and driver engagement.
It also adopts more powerful, distinctive styling inside and out, led by a dramatic interpretation of Lexus' hallmark spindle-shaped front grille arrangement.
Junichi Furuyama, IS Chief Engineer, explained: "We adopted an entirely different approach to the development of the new IS.
"Rather than develop each individual aspect in the hope they will combine to offer an engaging driving experience, we first established the kind of driving experience owners desire.
"With this as our initial premise, we then developed the individual performance elements to support it.
"Every aspect of the new IS has been engineered with a focus on sporting performance, agile handling, accurate response to driver input and highly communicative feedback."
The new IS benefits from a dozen Lexus-first features and technical innovations.
It also showcases an all-new interior that combines authentic Lexus quality and refinement with a more sporting and focused environment for the driver.
There is also best-in-class space for rear seat passengers and a larger, more user-friendly boot.