Jacob was born in Metz, Lorraine, France on May 8, 1958. A pianist by age 4, he was immersed in studying the French classics. Something of a child prodigy, Jacob had perfect pitch and natural talent. He did not discover jazz until age 10, but when he did, its improvised nature appealed to him immediately. Early influences were Dave Brubeck and Oscar Peterson. As a teen, Jacob studied under Pierre Sancan at the Conservatoire National Superieur de Musique in Paris. Later, he would teach piano at the Conservatoire National de Region in Metz.