The 22-year-old singer-songwriter beat off competition from AlunaGeorge and Laura Mvula and is the first male act to scoop the prize.
"I'm thrilled and honoured to win the Brits Critics' Choice Award," Odell said in a statement.
"I genuinely can't believe it. Thank you so much. Looking at the list of amazing female artists who have won the award already, I just hope I don't let the boys down!"
Watch Odell perform 'Sense' below:
The Critics' Choice Award is given to British acts tipped by critics for mainstream success in the forthcoming year who are yet to release their debut album.
Previous years have seen it awarded to Emeli Sandé (2012), Jessie J (2011), Ellie Goulding (2010), Florence + the Machine (2009) and Adele (2008).
The winner is chosen by a team of experts including the music editors of national newspapers, key music and lifestyle magazines, music websites and the heads of music at major radio and music TV stations.
Next year's Brit Awards take place on Wednesday, February 20 at London's O2 Arena and will be broadcast live on ITV1.
> Brit Awards Critics' Choice nominees: Who are they?
Watch a brand new interview with Tom Odell below: