Featuring the same engine, chassis and gearbox as the production model, the LX 570 entered by Joe Bacal was victorious in the Stock Full class, covering the 500-mile (804.6km) route through Mexico's Baja California peninsula in 19 hours and 56 minutes.
Bacal's 500 victory comes on the back of another class win in last November's Baja 1000.
At this year's 500, no other class competitors made it to the finish in a race that is notoriously tough on machinery. Bacal said he ran faster than smaller class competitors and even had the capacity to pull out stuck vehicles so they could continue the race.
"The  race was probably the most difficult to date; even harder than the Baja 1000 I raced last November due to flipped cars scattered all over the course and locals driving in the opposite direction to us," Bacal said.
"The LX ran perfectly in the 100 degree (38 degree Celsius) heat and cold desert nights.
"We caught some very fast drivers in much faster classes in the difficult silt and climbs where the two-wheel drive cars struggled," Bacal added.
Prepared by US-based JTGrey Racing, Bacal's racer features the roadgoing LX 570's 5.7-litre V8 engine, six-speed sequential automatic gearbox, chassis and electronics. The only modifications are the inclusion of safety equipment, including roll cage, racing suspension and 37-inch tyres to cope with the desert terrain.
Bacal also receives support from Australian automotive accessories company ARB.
Lexus Australia chief executive Sean Hanley said the LX had once again proven itself as the ultimate large luxury SUV for all conditions.
"LX 570 owners can travel to their destinations in supreme comfort supported by peerless engineering that has been proven time and again in the world's hardest motorsport events," Mr Hanley said.
"We are proud to see this hugely impressive vehicle continue its winning performances in the infamous Baja race."
The local market Lexus LX 570 was updated last year with enhanced exterior styling, including Lexus' signature spindle grille, and new 20-inch alloy wheels.
It also received a host of new comfort, convenience and driver assistance features, including selectable Multi-Terrain Select function, which delivers the ideal combination of stability and traction control assistance over different surfaces.