John Smith, 53, was last seen on Friday June, 25 after he was due to attend an appointment and failed to return home.
It is understood he is a security guard at the House of Frasers in Glasgow.
Sharing the police appeal, one Facebook user said: “Please share! He was a security guard in my old work and he was such a lovely man! Hope he gets home safe.”
Another said: “John is a security guard at HoF Glasgow and he's such a lovely guy.
“Please keep an eye out for him Hope he is found safe soon.”
Mr Smith was reported missing to police on Saturday morning and police enquiries are ongoing.
Police believe he may have been on Bond Street, Blackpool at around 10 am on Sunday, June, 27.
Mr Smith is white, around 5 foot 10 inches in height, medium build, with greying, auburn hair. He also wears glasses.
Officers have been checking CCTV footage for any further information on Mr Smith and where he might have gone.
Mr Smith often socialises in Paisley but no-one has seen or heard from him recently and concern for him is growing.
He also has links to Blackpool and Morecombe in Lancashire and officers are liaising with Force colleagues in those areas.
Anyone who has seen Mr Smith or has any information as to his whereabouts is asked to call Police Scotland on 101, quoting incident number 1164 of 26 June 2021.