Orso was born in Prunelli-di-Casacconi, a mountain village on the northeastern side of the Mediterranean island of Corsica, a regional department of France with strong historical and cultural ties to Italy.
Leaving the orphanage as a teenager he was reunited with his mother, supporting her while working during the day as a baker, butcher, and mason, and singing in the evening at parties and with friends.
He also wrote the minor French hits Ma vérité c'est toi (You are My Truth), Le veston à carreaux, (The Plaid Jacket), L'enfant de la rue (The Street Child) and L'ami tu nous reviens (The Friend Who Came Back).
Since then he is the only performer to have participated in all of the very popular, annually held 60's and 70's nostalgia reviews Âge tendre, la tournée des idols (Tender Age, the tour of idols) – formerly called Âge tendre et têtes de bois (Tender age and wooden heads, a popular song by Bécaud).
As of 2015 Michel Orso still performs regularly, occasionally alongside friend and musician François Grimaldi at the Corsican restaurant-cabaret Le Lamarck in Paris' Montmartre district.