Blair Wilson posted a photo online of him smiling despite having blood running down his face following the assault.
He was attacked while walking on Main Street in his home town of Neilston, East Renfrewshire.
Police said a man shouted homophobic comments at him before approaching him and kicking and punching his face and body.
Nicola Sturgeon spoke about the 21-year-old in a speech at Glasgow’s annual Pride celebrations on Saturday, praising him for speaking up “instead of cowering away”.
She said he demonstrated “dignity, courage and compassion”.
Now, police have issued an appeal for witnesses to the assault on June 29.
They said the suspect is white and slim with dyed blond hair.
He was wearing a dark jacket and carrying a blue backpack with a green palm tree pattern.
He was accompanied by another man and three women.
Sergeant Nik Rossi at Giffnock Police Office said: “We have been carrying out extensive enquiries since the assault was reported including reviewing CCTV footage and interviewing local people.
“However, I am now appealing for anyone who may have been in the area, which would have been busy at the time and who has information which can help identify the person responsible to get in touch via 101 quoting incident number 5076 of 29/6/2018.
“Information can also be given to Crimestoppers anonymously on 0800 555 111.”