He spent the majority of his 15-year playing career with A.S. Roma, and was regarded by supporters as a club symbol, before his successor in the number-10 shirt and offensive midfield playmaker role, Francesco Totti.

He played 47 times for Italy and starred in the teams that reached the semi-finals of the 1988 UEFA European Championship, and subsequently the 1990 FIFA World Cup on home soil.

[4] In 1996 Giannini left Roma to play in Austria for Sturm Graz, with whom he spent just half a season before returning to Italy due to homesickness.

[6] Throughout his career, Giannini was often referred to as "Il Principe" (The Prince), and was described as a "fantasista," due to his creative ability, elegance, technique, vision, and passing range, which made him an effective playmaker.

Later that year, Giannini then served as coach of Romanian side Argeş Piteşti, but was axed in October after nine consecutive defeats, and replaced by Dorinel Munteanu.

[citation needed] Despite an impressive first half of season with Gallipoli, who was hailed as one of the main league surprises, Giannini resigned from his managerial post on 8 February 2010 following a 2–2 home draw to Grosseto characterized by the team players stopping for 40 seconds and turning faces towards the stadium stands as a form of protest for not having been paid any monthly salaries since October 2009.

[27] After a string of unimpressive results, Giannini stepped down again on 22 March together with his aides Roberto Corti, Fabrizio Carafa and Franco Mandarino, defining his resignations as "irrevocable".

[28] In June 2010 he agreed a two-year contract as head coach of fallen giants Verona, with the aim to guide the scaligeri to promotion from the Lega Pro Prima Divisione league.

[citation needed] He returned into management in June 2017, being appointed head coach of recently relegated Serie D club Racing Roma.