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.
Alessandrini was also present in Il Giornalino with 'Ai Confini dell'Avventura', 'Storie di Tutti i Tempi' and 'Rosco & Sonny' (with scripts by Nizzi), and cooperated on some episodes of Berardi and Milazzo's 'Ken Parker' series. For the magazine Supergulp of the publishing house Mondadori, he illustrated the first episodes of the 'Allan Quatermain' series, the precursor of 'Martin Mystère'.
Rosco & Sonny - Lo Scippo (Il Giornalino #46, 22/11/1981)
With Castelli, he contributed to the Bonelli titles 'Mister No' and 'Long Rifle', before embarking on their best known series, the one about the adventurous archaeologist 'Martin Mystère' in 1982. Many artists have drawn the series, but Alessandrini remained the main artist, illustrating various episodes and all of the covers. The series was featured in Bonelli's new magazine Zona X in 1992, for which Alessandrini additionally drew several covers.
In addition, Alessandrini teamed up with Roberto Dal'Pra and produced 'L'Uomo di Mosca' in the magazine Torpedo in 1990 and 'Anastasia Brown' in Comic Art in 1991. In the magazine Comic Art, Alessandrini established himself as an allround author, writing and drawing 'Fatti e Misfatti a Planet Arium', a series of short gags.
Between 1993 and 1995, he drew comics based on the 'Indiana Jones' films with scripts by Claude Moliterni for the French publishing house Bagheera. In 2001, he illustrated the fantasy saga 'Outremer' with scripts by Beretta, which was published in France by Albin Michel between 2001 and 2003. In 2007, he made the drawings for the fifth installment in Frank Giroud's 'Quintett' project, that was published by Dupuis.