The 27-year-old was walking along Auchinlea Way, Easterhouse, when he was approached from behind and assaulted by a youth.
It happened at around 11.50am on Saturday.
The suspect is described as white, male, around 18 or 19, stocky, and with short dark hair.
He was wearing a white hooded top and white jogging or tracksuit bottoms.
Constable Jenna Nelson said: "This would appear to be an unprovoked and random attack.
"Auchinlea Way leads to the Glasgow Fort and is near the M8 so can be busy with traffic.
"I would appeal to anyone who may have witnessed the attack to contact police."