[1] Its design origins can be traced back to the Mitsubishi SSU which debuted at the 1999 North American International Auto Show, although the Endeavor does not share the concept's mechanical underpinnings.

[3] When the Endeavor debuted in March 2003, it used the 6G75 3.8-liter V6 offering 215 hp (160 kW) and 250 lb⋅ft (339 N⋅m), mated to a four-speed automatic transmission with an optional all-wheel-drive system that splits the torque 50/50 by default.

Despite some reasonably favorable reviews on its release,[4] the Endeavor's performance in the marketplace failed to meet Mitsubishi's expectations.

In April 2004, the Endeavor received a mid-year upgrade, improving standard equipment which now included daytime running lamps, dual-stage airbags with occupant sensors in front, and a tire-pressure monitor amongst others.

Some versions received additional upgrades, such as standard side impact airbags on the XLS, while new options included a rear-seat DVD system and traction and stability control.