The man, who is said to have been known locally as Raqib, appears in the 13-minute There Is No Life Without Jihad video alongside 20-year-olds Nasser Muthana and Reyaad Khan, both from Cardiff.
The trio urge their countrymen to come to fight for the Sunni Muslim militant group, Isis, in Syria. The rebels' presence has grown since the country was plunged into civil war, and in recent weeks Isis fighters have swept through Iraq, taking control of cities including Mosul and Tikrit.
Raqib, identified in the video as Brother Abu Bara' al Hindi, is understood to have come to Scotland from the Sylhet District in north-eastern Bangladesh as a child and to have gone to school in Aberdeen.
He reportedly attended St Machar Academy and grew up in the Froghall area of the city.
Holding a gun in the video, he said: "Are you willing to sacrifice the fat job you've got, the big car you've got, the family you have?
"Are you willing to sacrifice this for the sake of Allah? Definitely! If you sacrifice something for Allah, Allah will give you 700 times more than this."
He added: "All my brothers living in the west, I know how you feel.
"When I used to live there, in the heart you feel depressed. The cure for the depression is jihad."
One former acquaintance, who said he had not seen Raqib for a couple of years, expressed shock at recognising him in the footage.
The man, who declined to be identified, said Raqib had been a troublemaker as a teenager but appeared to have calmed down and become more "humble" as he became more religious.
He told the BBC: "He came here when he was a younger child. He went to primary and secondary school here.
"After that he was around in Aberdeen. He was a bit arrogant. A bit aggro, maybe something to prove. He ended up in a lot of fights. To learn he's accepted religion in such an extreme way is a bit shocking. Shocking because he's a youth from Aberdeen who's ended up somewhere like that."
The man said that, when he was younger, Raqib had enjoyed drinking alcohol and going to nightclubs.
If any trouble or racial abuse came his way, he "sorted it out with his fists", he added.
Another acquaintance in Aberdeen, who knew Raqib through the city's Muslim community, said he was "more of a lad than a regular attendee at the mosque".
The unnamed acquaintance continued: "He was a happy guy, played football - he was a good player and he supported Aberdeen.
"I remember him as a hyper person, energetic and loud … not the type of person you'd expect to go and do this."
Ibrahim Alwawi, from Aberdeen Mosque, told the BBC: "We, as a Muslim community in the city of Aberdeen, are shocked like everybody else. We are co-operating with the authorities as we usually do."
The latest revelations come amid calls to remove the controversial video from YouTube.
A Downing Street spokeswoman said the Government had already succeeded in removing 15,000 pieces of extremist material from the internet since starting a drive in December to block jihadist terrorists from using online messages to recruit Muslims in Britain to their cause.
She said: "We will keep working to do all we can to make sure there is not material online promoting terrorist activity."
Meanwhile, former Prime Minister Tony Blair appeared to backtrack on previous claims that the US-led invasion of Iraq in 2003, backed by the UK, was not linked to the chaos currently engulfing the country.
He said yesterday that the current situation was "in part, the imprint of the removal of Saddam Hussein 11 years ago".