He was born in Trieste, then Zone A of the Free Territory of Trieste, now part of Region Friuli-Venezia Giulia, Italy. His last name is of Slovenian origin. During his youth, he was a leader of the nationalist right wing Youth Front ("Fronte della gioventù") and then of the Italian Social Movement – National Right of Trieste. He was also a member of the City Council of Trieste. In 1977, Almerigo Grilz was the leader of Trieste section of the Youth Front, becoming the Deputy National Secretary by a direct appointment of then secretary Gianfranco Fini. During this time he was also a member of the Journalist order of Trieste and cooperated with the "Dissenso", the official journal of the Youth Front.