The accident happened near Altendorf between Zurich and Chur at around 5pm, Zurich police said in a statement.
For reasons as yet unknown, a 21-year-old was driving in the direction of Chur when the car touched the road's outer guardrail. As the driver was steering the car back into the motorway lane, the vehicle brushed a passing van driven by a 34-year-old.
The van then went out of control, struck the central reservation and collided with a car in the opposite lane.
The 52-year-old driver of that third vehicle was killed. The two other drivers were taken to hospital with unspecified injuries.
The exact cause of the accident is unknown, say police, though 20 Minuten speculated that it could have been black ice on the road.
Following the accident the road was closed in both directions until around 9pm, said the paper.
Witnesses to the accident should call police on 044 247 22 11.