The Argentine will replace Andre Villas-Boas at the Ligue 1 side and will work under a new club president, Pablo Longoria, who was promoted to the top job by l'OM owner Frank McCourt.
The Club announced on Friday:
"Frank McCourt announces profound changes, opening a new chapter for Olympique de Marseille
"Pablo Longoria is appointed president of the management board of Olympique de Marseille. Internationally renowned coach Jorge Sampaoli is appointed head of the first team."
“I've been told all my life that l'OM is a passion. Let the Orange Velodrome light up when the team goes to the stadium.
“Marseille is a people's club and I feel myself in this heat. We are not here to hide: we will play hard.
"When I received this proposal, I dreamed of being able to party in the city. In the world, there are quiet places and intense places. These are the ones I want and I accepted without hesitation. This club has a soul that's why we are here. We are ready. "