Introduced in May 1990, the Estima was originally developed for the fast-growing North American minivan market with the aim of presenting a new minivan concept. The spacious cabin that comfortably accommodated 7 passengers was made possible by tipping the engine at a 75-degree angle and installing it under the center of the floor, thereby also adding to the maneuverability and stability of the vehicle. The unique external styling, which resembled the shape of an egg, was developed by Calty Design Research, Inc., Toyota's design studio based in North America. Reflecting these innovations, "an ingenious egg" was used as a catch phrase in Japanese ads. Initially, a 2,438 cc "high-mecha" twin-cam engine (2TZ-FE) that produced 135 PS was the only engine available for the model, until a new 160 PS supercharged engine was added in 1994. The 4-wheel independent suspension system used MacPherson struts in the front and double wishbone in the rear. The available drivetrain configurations included rear-wheel-drive and 4-wheel-drive. The 4-speed automatic column-shift transmission allowed walkthrough access from the first to the second row.

In February 1993, a low-priced 8-passenger model was added to the lineup, replacing the second-row seats with a 3-seat bench and the rear suspension with a 4-link type. The underfloor midship engine configuration was abandoned after the first generation, and all subsequent models adopted a conventional front-engine layout.

The Estima was marketed in the United States and Europe as the Previa.