Real Sociedad de Fútbol was founded on 7 September 1909 in San Sebastián, the elegant resort capital of Spain's Basque Country. The "Real" (Royal) prefix was granted by King Alfonso XIII in 1910. Like neighbours Athletic Bilbao, Real Sociedad historically operated under a Basque-only player policy, but the rule was relaxed in 1989 with the signing of Liverpool's John Aldridge — opening the door for foreign and non-Basque Spanish players. The club has played at the Reale Arena (Estadio Anoeta) since 1993, currently capacity 39,500.
Real Sociedad's golden era arrived under Alberto Ormaetxea in the early 1980s, with back-to-back La Liga titles in 1980-81 and 1981-82 — the only league championships in club history. The 1981-82 squad — featuring Luis Arconada, Roberto López Ufarte, Jesús María Satrústegui and José Mari Bakero — denied Athletic Bilbao what would have been a third consecutive Basque Liga title. The two Basque clubs' simultaneous dominance through 1980-83 made the early 1980s the most decorated period in Basque football history.
The modern era saw Real Sociedad establish themselves as a stable La Liga side and a renowned developer of elite talent. The Zubieta academy has produced Xabi Alonso (currently the celebrated Real Madrid manager and 2024 Bayer Leverkusen Bundesliga winner), Mikel Arteta (Arsenal manager), Antoine Griezmann (briefly), Mikel Oyarzabal, Martin Ødegaard (loan), Kepa Arrizabalaga (briefly) and Mikel Merino. The club won its third Copa del Rey in 2020 — staged in 2021 due to the pandemic — defeating Athletic Bilbao 1-0 in the most-anticipated Basque Derby final ever. The Basque Derby (Euskal Derbia) defines the club's cultural identity.