Based on the island of Sardinia, Cagliari was founded in 1920 when some students of the city was challenged by some Genovese sailors, who arrived to the island on a steam ship.
The first official tournament the team partecipated in was in a small league called Divisione Meridionale. The first season the team was only made of Sardinians but when Cagliari lost the final in the Divisione Meridionale in 1929/1930 the team started to look at the Italian Peninsula for reinforcement. The year after they made progress to Serie B after the new league structure by the guidance of Hungarian trainer Ernst 'Egri' Ernstein.
While the team was on its way up it was fighting with financial problems and in 1935 the team had to be refounded (CAXI: is this a a word I just made up?) the same year with the consequence that the team had to start all over again in the last divison: Seconda Divisione.
Hereafter the team advanced to Serie C in 1937 and from then on fighted between Serie C and Serie B. They finally reached Serie A in 1964 for the first time in their history. Cagliari was lead by Luigi Riva, the all-time topscorer for the Italian National Team, and the biggest legend in Cagliari playing there from 1963-1976. He gave the team its first succes in Serie A being the topscorer in 1966/67 season. This achievement he did again in two other seasons. Cagliari had their so far best season in 1968/69 when they became runners-up in Serie A, and the year after they won their, so far only, Serie A title. This was the first time a Southern Italian team achieved this.
After their Scudetto season the team started to decline again, especially because Luigi Riva had some serious injuries, and fell back to Serie B already in 1976. Cagliari elevated between Serie A and B the seasons to come but their biggest blow came in 1986 when they were involved in the match fixing scandal 'Totnero'. Cagliari was punished with -5 points in Serie B and thus didn't survive and got relegated to Serie C1.
The team didn't give up and already in the season of 1990/1991 they were back in Serie A. During this seasin the team changed ownership to Massimo Cellino, who is still president today. The team was developing good results and in 1993/94 season the team achieved it's so far best record in Europe, reaching the semi-finals of the UEFA Cup.
Once again the team couldn't keep consistency and relegated to Serie B in 1997. The team came back to Serie A in 2004, thanks to trainer Edoardo Reja, where they have been since. The latest seasons it has been common to see Cagliari changing coaches often: since 2004 the team has changed coaches 14 times by 10 different coaches.
Despite that the team has consolidated itself in the middle of Serie A and are now trying to build a team up to fight for European spots.