The larger, fourth generation ES (designated MCV30) debuted in 2002, one year after the Lexus IS became Lexus' entry-level car. The presence of the IS in the Lexus lineup enabled the company to give the new ES 300 a more upscale image and luxury feel by excising the sporting pretensions of the previous ES models. Compared to its predecessor, the new ES possessed an interior with a greater emphasis on comfort, superior NVH isolation, larger and softer seats, and improved interior materials. The cabin was fitted with California Walnut wood trim on the front dashboard, center console, and doors. Exterior puddle lamps, floor-well lighting, chrome door handles, and rear-view mirrors that would automatically tilt downward in reverse gear contributed to a more upscale feel. Available options, including a power rear sunshade, rain-sensing windshield wipers, a DVD-based navigation system, and a Mark Levinson premium stereo system, were similar to features on the flagship LS 430 sedan.

Despite the additional features and added weight, neither the acceleration nor the handling of the ES suffered. Other new features included a drive-by-wire electronic throttle, a five-speed automatic transmission, anti-lock brakes with electronic brake-force distribution and brake assist as well as stability and traction control. On the exterior, the ES gained a more rounded shape than its predecessor, with pulled-back headlamps and a single-tone color scheme with chrome trim. New design elements similar to the LS sedan included a rear quarter window and wrap-around taillamps with a diagonal edge. In Japan, the MCV30 Windom received a 2-star LEV rating. The fourth generation Lexus ES was built in Kyushu and Tsutsumi, Japan.[5]

For the 2004 model year, the American market received a new 3.3 L engine producing 225 hp (later revised to 218 hp, because of changes in SAE power testing procedures), and the car was renamed the ES 330. In the Middle Eastern and Asian markets, however, the 3.0 L engine was still available.

In 2005, the ES received a facelift with new front and rear fascias, clear taillights, projector headlights, and a redesigned grille. Inside, new features included power adjustable pedals and heated and ventilated front seats. Additionally, new Bird's Eye Maple trim brightened the interior and integrated satellite radio was offered as an option. In 2004, the limited ES 330 "SportDesign" special edition featured the Adaptive Variable Suspension, 16-inch Y-spoke alloy wheels, Mark Levinson audio, interior upgrades, and special dark exterior colors. Lexus also offered an exclusive ES 330 "Black Diamond Edition" in 2005, featuring black wood trim, iridescent Black Diamond paint, and a set of Tumi luggage.

The fourth generation ES 300/330 continued the solid success of the ES series for Lexus. Despite an increase in price befitting its more upscale amenities (2002 base price of $32,080), ES sales jumped to 69,607 in its first year, making the Lexus ES the best-selling luxury car in the United States.[3] Throughout its production run, the fourth generation ES was Lexus' best-selling sedan, and outsold only in the Lexus model range by the RX luxury utility vehicle.