The Proton Waja is the first model designed in-house by Proton. The development of the Waja began at the end of the 1990s together with the Campro engine, however the development of the Campro engine was still in progress at the time of its launch and therefore Proton had to source the 4G18 engine for the Waja from Mitsubishi,^{[citation needed]} before switching to Campro engines in 2006. It was launched in August 2000 together with the introduction of Proton's new corporate logo. Early batches of the Waja had some serious quality problems due to some component vendors and suppliers skipping quality checks to rush for the huge early demand.^{[citation needed]} However, the quality of the components were strictly improved years later in 2005.^{[citation needed]}

The Waja was facelifted twice since its debut in August 2000. The first minor facelift was in mid-2006 which only involved rear lights. The 2007 Proton Waja with a more substantial facelift was launched on January 19, 2007 together with the facelifted Proton Savvy. For the 2007 Waja, it was given a new grille which was nearly identical to the Savvy. The 2007 Waja also includes both ABS and air bag as standard for the Malaysian market, which were previously optional equipment. At the end of 2005, Proton additionally introduced another variant of the Waja, known as Proton Waja Chancellor, to be used byrepresentatives of the Association of Southeast Asian Nations (ASEAN) during the meeting of ASEAN leaders in the KLCC, shortly before its launch in 2006. The Waja Chancellor has a longer wheelbase and a 2.0 L V6 engine similar to that used in Proton Perdana V6, also sourced from Mitsubishi. by2008, an updated Waja was launched with an improved Campro engine and a new center console with a new 2-DIN Clarion audio set.

Waja sales in the UK, where it is rebadged as the Impian, did not begin until April 2001, and it has continued virtually unchanged ever since. The Impian is only available with right hand drive while left hand drive models are available elsewhere in Europe as the Waja. Sales have not been strong,^{[citation needed]} as it was behind the best of the competition at its launch and virtually all of its competitors have been replaced since. Its decent ride and handling, generous equipment levels, competitive asking price and comprehensive aftersales package are perhaps the only things that keep it going with British buyers