FC Sion were founded in 1909 by Robert Gilliard, who became club captain, and played their first match the same year, a 3–2 win against FC Aigle. The club grew thanks to contributions from locals, and played their first competitive league fixture in 1914, again a 3–2 victory, against FC Monthey. In 1919, Sion formally organised its managerial structure, with Gilliard becoming vice-president and Charles Aymon taking the presidency.
