Police were called at 9.48pm on Friday, 11 March, to a car in collision with a pedestrian and subsequently a house on the eastbound A406 in Neasden.
The pedestrian – a man aged in his 30s – was pronounced dead at the scene.
Enquiries are ongoing to trace his family, believed to be overseas.
A passenger in the car – a man aged in his 50s – was taken to hospital. His condition remains life-threatening.
The driver of the car – a man aged in his 40s – was arrested on suspicion of causing death by dangerous driving. He has also been taken to hospital, where his condition is not life-threatening.
Detectives from the Serious Collision Investigation Unit are investigating. Any witnesses or anyone with dashcam footage are asked to call them on 020 8246 9820, ref 7729/11mar.