Platini's three years at Saint-Étienne were a mixed success. The club had signed him with a view to success in the European Cup, but despite some excellent results (including a 6-0 win over PSV Eindhoven in the 1979-80 UEFA Cup and a 5-0 win at Hamburg in the UEFA Cup the following season), the club were unable to surpass the feats of the Saint-Étienne side that had reached the final of the 1976 European Cup.

Platini won the French league title in 1981 with 'Les Verts', but was on a losing Saint-Étienne side in two French Cup finals, against Bastia in 1981 and against Paris Saint-Germain in 1982, in what was his last match for the club before joining Juventus. He left for a nominal transfer fee (under UEFA regulations) despite being out of contract and no fee being necessary under French regulations at the time.