According to the club's statement on Monday, Louis-Dreyfus and her family will retain a small stake, reports Efe.
McCourt, former owner of the Los Angeles Dodgers baseball team, said: "To participate in the history of Olympique de Marseille and guide the club to success, both on the pitch and off, is an honour and privilege for my family and myself."
McCourt, 63, said that Olympique is both one of the oldest and most respected clubs in the world, as well as the only French team to have won the Champions League and the Union of European Football Associations (UEFA) Cup.
McCourt explained his four strategic objectives, the first of which is to build a team that can regularly fight to win Ligue 1.
The other objectives are to create the best environment for fans, integrate the club into the city and constitute a solid organisation inside and outside the field.
