The incident happened at about 1.05am on Sunday on the A68 near Pathhead.
The 19-year-old was walking along the southbound carriageway when he was involved in a collision with a Volkswagen Transporter van.
He was taken to the Edinburgh Royal Infirmary where he is currently being treated for two broken legs and a broken collarbone. The injuries are not believed to be life threatening.
Police responded and closed the road for around five hours while they carried out an investigation and are now keen to hear from anyone who can assist with their enquiries.
A police spokesman said: “Anyone who was on the A68 at the time and witnessed the collision is asked to come forward immediately.”