Andrew Hendry, 20, appeared at Falkirk Sheriff Court today, and was jailed for two years and four months.
He had previously admitted a charge of assault to danger of life.
The attack happened in the early hours of Saturday, March,13 on Stirling Road in Tullibody.
The elderly man was walking east when Hendry approached him and assaulted him.
The man needed hospital treatment.
Hendry was arrested near the scene.
Detective Constable Debbie Reid from Stirling CID,, said: “This was a despicable act of violence and a completely random attack.
“Hendry was under the influence of drink and drugs with his actions leaving lasting scars for the victim and his family.”He added: “I hope that the sentence will offer them some closure.
“I would like to thank the victim, along with witnesses who assisted with our investigation.”