Rifleman Dave Curnow served in 4 Rifles Battalion in the British Army including a tour in Afghanistan two years ago.
He was found with head injuries in Redruth, Cornwall, in the early hours of 20 September and died in hospital.
A funeral ceremony with full military honours was held at Truro Cathedral, where a large poppy wreath was laid.
City centre streets were lined with people as the hearse made its way to the cathedral.
Michael Wearne, from the Royal British Legion Riders Branch, said: "It's affected everybody big time... This kind of thing should never happen."
Police arrested two men following the disturbance outside The Zone nightclub.
Connor Hammond, 21, of Johns Park, and Liam Laing, 21, of Brookside, Chacewater, are due to stand trial charged with murder.
Hundreds of people have attended a funeral service for a 20-year-old soldier found injured "after a disturbance" outside a nightclub.