Giancarlo Alessandrini was born in Jesi, in the Italian province of Ancona. He entered the world of comics in 1972. After illustrating several stories for pocket publications, he started working for the magazine Il Corriere dei Ragazzi, where he began a collaboration with the scriptwriter Mino Milani. His first story was 'Il Cifrario del Maggiore Martin', an episode in the series 'L'inviato nel Tempo'. Alessandrini also cooperated with scriptwriters like Pier Carpi, Manocchia, Alfredo Castelli, Ventura, Selva and Maltese. With Milani, he created the fantasy series 'Anni 2000' in 1973, followed two years later by 'Lork Shark'.
By now, Alessandrini had joined the Giolitti studios, where he began a large production of comic stories for foreign publishers. He illustrated various war stories for the British Fleetway Publications, which were mostly published in Battle. He also continued to work for the Corriere dei Ragazzi, this time with the series 'Il Maeatro'. He left the magazine after a dispute with the editor however, and afterwards, drew the spin-off series 'Eva Kant' (the partner of 'Diabolik') with scripwriters Castelli and Gomboli in the Italian Cosmopolitan. He was assigned by the publishing house Bonelli to illustrate some installments in the collection 'Un Uomo un'Avventura', with scripts by Castelli.