The third generation LS 430 debuted in 2001.

In January 1989, the Lexus LS 400 (chassis code UCF10), made its debut as the first flagship of the Lexus line at the North American International Auto Show in Detroit, Michigan.[28] The first Lexus dealerships in the U.S. began sales of the LS 400 in September 1989. Limited exports to Europe began in 1990.[29] Although the LS 400 was initially conceived as a standalone model, in the U.S. and other markets it was ultimately sold alongside the ES 250, an entry-level luxury sedan that was produced to give dealers a second product offering.[30] In Japan, the launch of Lexus was complicated by Toyota's existing five domestic dealership networks,[31] several of which sold Japan-only Toyota luxury models.[32] As the design of the Lexus flagship advanced, domestic dealers' requests for a Japanese market version grew,[5] and a right-hand drive, Toyota Celsior-badged version was introduced shortly after the LS 400's U.S. debut.

The Celsior, named after the Latin word for 'supreme', was largely identical to the LS, but offered additional trim specifications.[33] By 1991, on the strength of the LS 400's sales success, Lexus became the top-selling luxury import in the U.S.,[34] and subsequently the top luxury make in the country overall.

In 1993, a mid-cycle refresh was introduced to the LS 400,[36] and a similar practice of updates was adopted for following generations. In 1995, Lexus unveiled the redesigned, second generation LS 400 (UCF20), featuring a longer wheelbase with similar styling and specifications as the original model.[37] Production of the second LS 400 followed the same cycle as the original, lasting from 1995 to 2000, with a mid-cycle refresh in 1998.

The third generation LS 430 (UCF30) premiered in 2001 at the North American International Auto Show, introducing a new body design and a host of new interior and technological features.[38] Production of the LS 430 lasted until 2006, marking the last occasion the Lexus flagship was produced in a single body style. The same year also saw the end of Toyota Celsior sales with the long-awaited introduction of Lexus Japan and the arrival of new generation Lexus models.