The Manchester United boss has thrown his weight behind an initiative by city tycoon Sir Willie Haughey to save a generation facing joblessness.
He is lobbying hard for the Youth with Hope scheme which, among other things, looks to get firms to hire youngsters as "green champions" – and pay for their wages by cutting energy costs.
Sir Alex said: "I am absolutely delighted to support the Youth with Hope campaign and I would urge every business in the UK to get on board."
Sir Willie has already secured the support of major environmental organisations and fellow business people for his initiative.
The entrepreneur reckons companies can cover their costs relatively simply.
Sir Willie hired a young graduate as a green champion for his Gorbals HQ, to make sure lights and heating were switched off when they weren't needed. The savings made more than paid for the new post.
Govan-born Sir Alex is a major signing for Sir Willie.
With the football legend's backing, Youth with Hope will reach a UK-wide audience.
Sir Willie has secured other ambassadors too – including fellow tycoons Sir Brian Souter, Sir Tom Hunter and Michelle Mone.
Youth with Hope has already secured pledges to create 254 jobs for young people.
These include 20 announced by Glasgow City Council leader Gordon Matheson earlier this month.
Sir Willie hopes other local authorities will realise that they could save on their heat and power bills by appointing young Green Champions.
Tennent Caledonian Breweries have also pledged to recruit green champions.
Sir Willie, however, hopes his initiative can grow across the UK.
Tonight he is scheduled to appear on BBC TV's The One Show to talk about his project.
The tycoon reckons business should not wait for politicians to act on youth unemployment. It just needs half of all firms to hire a young person to wipe out youth unemployment.
He said: "There are 2.8million businesses in the UK and 1.3m unemployed youths. You do the maths."
For more information, or to sign up, see websites youthwithhope.co.uk and greenchampions.co.uk