Jémez was born in Las Palmas, Canary Islands. During his career he played for Córdoba CF, Real Murcia, Rayo Vallecano (first appearing in La Liga and playing all 38 matches of the season), Deportivo de La Coruña (only totalling ten games in his first two seasons as the club achieved two consecutive runner-up spots, being more used afterwards) and Real Zaragoza, which he helped to the 2001 conquest of the Copa del Rey.