Real Sociedad was founded in September 1909 as Sociedad de Futbol. The following year, King Alfonso XIII granted the club royal patronage, with the name changing to Real Sociedad de Futbol. Today, the club is more popularly known by the simplified 'Real Sociedad'.
For a long time, Real Sociedad insisted on only signing Basque players, similar to the policy currently operated by Athletic Bilbao. This policy was ended in 1989, when Ireland international John Aldridge joined the club. A year later, English striker Dalian Atkinson also signed for Sociedad.
The 1980s was by far the most successful decade in Real Sociedad's history. After finishing as league runners up in the 1979-80 season, the club won the Primera División for the first time in 1980-81, finishing ahead of Real Madrid on goal difference. The following season saw Real Sociedad successfully defend their La Liga crown, this time finishing two points ahead of second-placed Barcelona. In 1982-83, Sociedad reached the semi-finals of the European Cup and in 1986–87, the club won the Copa del Rey, beating Atlético Madrid via a penalty shootout. In recent seasons, the club's best performance came in 2002-03, with Real Sociedad finishing as runners up to Real Madrid, gaining the club Champions League qualification for the first time.
Legendary Real Sociedad players include the league winning trio of Jesús María Satrústegui, Jesús María Zamora and Pedro Uralde; the afforementioned John Aldridge; Xabi Alonso, who won the Don Balon award for his performances in the 2002-03 season and Turkish striker Nihat, who scored 59 goals for the club in his five seasons there.
The club plays its home matches at the Anoeta Stadium, which opened in 1993. The stadium has a capacity of 32,076 and also occasionally hosts rugby union matches for the French sides Biarritz Olympique and Aviron Bayonnais.