Juncker triumphed today at a European People's Party convention in Dublin, where he defeated Michel Barnier of France.
Juncker received 382 votes to 245 for Barnier, the EC's current internal markets minister.
Juan Manuel Barroso, the conservative bloc's previous choice, is stepping down as commission chief after 10 years in the job.
The winner faces a tough challenge to become president versus European Parliament leader Martin Schulz, the Socialists' candidate for EC president.