Born in Anagni, at the age of sixteen Colacicchi moved to Florence to complete his classical studies, but soon devoted himself entirely to painting under the guidance of Francesco Franchetti. In 1926, together with Alberto Carocci, he was among the founders of the magazine Solaria. In the same year he participated for the first time in the Venice Biennale and in the Prima Mostra del Novecento Italiano. From then on, he appeared in all the major national and international exhibitions. A friend of poets, writers, musicians, intellectuals and men of culture, Colacicchi was at the centre of Florentine artistic life in the period between the two wars. In 1944, he joined the Partito d'Azione and was a member of the Tuscan Committee for National Liberation, chaired by Carlo Ludovico Ragghianti. His cultural and civil commitment continued in the 1950s, as Director of the Accademia di Belle Arti in Florence, and as an art critic on the third page of La Nazione. Among the large-scale works, executed already in the second half of the 1930s, we note: the decoration of a hall of the Accademia Aeronautica in Florence (1937), the large composition The Judge of Locri for the hall of the Tribunale Civile in the Milanese Palazzo di Giustizia  (1939), the Allegory of the Arts for the Gambrinus cinema in Florence (1948), a frieze for the main hall of the Banca Commerciale in Florence (1962). In 1963 he executed two altarpieces, The Annunciation and the Pietà, for the Collegiate Church of Frosinone. Among the public galleries that own his works are the Galleria d'Arte Moderna in Rome, the Galleria Comunale in Rome, the Galleria d'Arte Moderna in Palazzo Pitti in Florence, the Gabinetto Disegni e Stampe and the collection of self-portraits of the Uffizi Gallery, the Galleria d'Arte Moderna in Milan. He has held numerous solo exhibitions in the main Italian cities.