Libero Marchini played for eight different clubs in the period between 1930 and 1942. He made his début in 1929-30 with Sarzanese and played two seasons in Carrara, from where he was signed by Fiorentina, which marked his début in Serie A. In 1934 he moved to Genoa 1893 in Serie B, winning the championship and being promoted to Serie A. The following season he remained in Serie B with Lucchese, winning his second consecutive Serie B championship in 1936. In 1937 he competed for Lazio Roma in Serie A. Due to disagreements with the management of the club, however, he was kept out of the team in the second year. In 1939 he changed to Torino FC and, the following year, returned to Lucca in the lower division. He ended his career in Carrara in 1943.
As a midfielder, Marchini’s good technique and ability to go forward seemed to have great promise. He had his best years with Lucca, being called to participate in the Olympics, where he played all four matches, and winning another cap in 1936. In addition to these five appearances, he made three more with the national B team, scoring one goal. After his football career he opened a restaurant in the Carrara region and later a newsstand in Torino. Like his father, an architect, Marchini was an anti-fascist and anarchist.