The Scottish singer-songwriter triumphed over second-placed singer/rapper Maverick Sabre and third-placed soul artist Michael Kiwanuka to claim the prize, which is chosen by a panel of industry tastemakers.
Sandé - whose debut album Our Version of Events is due for release in February - said: "To win a Brit Award so early in my career is beyond a dream come true.
"I am overwhelmed to be the recipient of such a prestigious award. Thank you so much."
Sandé - who joins previous Critics' Choice winners Jessie J, Ellie Goulding, Florence + the Machine and Adele - will perform at the Brit Awards nominations launch at London's Savoy Hotel on January 12, 2012.
The Brit Awards take place on February 21, 2012 at The O2 and will be hosted by James Corden.
> Blur to receive 'Outstanding Contribution to Music' Brit Award
> Brit Awards unveil 2012 award statue
Watch celebrities including Emeli Sande talking to Digital Spy about their favourite Christmas songs below: