It happened at about 9pm on Saturday, September 12 when the van driver came across a serious crash on Penistone Road in Huddersfield.
A BMW had crashed into a lamppost and was on fire, leaving the driver trapped inside.
The Sainsbury's worker attempted to free the trapped driver and used his van fire extinguisher to tackle the blaze.
He then ran to a nearby pub to get another extinguisher to use before fire crews arrived on the scene.
PC Dave Cant, known as 'Traffic Dave' on Twitter, took to Twitter to highlight the delivery driver's bravey.
PC Cant said: "Hey Sainsbury's. One of your home delivery drivers saved someone's life tonight!
"He came across a serious RTC, car on fire, driver trapped, tried to free the driver, used his van extinguisher then ran to a nearby pub to fetch theirs to use! #Huddersfield #Hero #Topbloke"
A West Yorkshire Police spokesperson confirmed that a man in his 30s suffered serious injuries.
He was taken to Leeds General Infirmary for medical treatment.
His injuries are not thought to be life-threatening.
PC Dan Williamson, from the Roads Policing Unit, said: “This was a terrible collision whereby the driver sustained serious injuries. I would like to thank members of the public who came to the assistance of the driver in the immediate aftermath.
“I would also like to appeal to anyone who witnessed the collision or saw the blue BMW prior to the collision to come forward, in particular anyone who has dashcam or CCTV footage.”