Marseille name Gattuso as new coach following Toral resignation
"I am very happy and proud to join Marseille - a club and a stadium, the Velodrome, in which I had the opportunity to play and which is famous throughout Europe for the passion and fervour that emanates from it," the 45-year-old Italian said in a statement.
Gattuso has notably been in charge at AC Milan and Napoli but has been a free agent since leaving Valencia at the beginning of this year.
A World Cup winner with Italy during a highly successful playing career spent mainly at Milan, Gattuso had recently been linked with Marseille's French rivals Lyon.
Marseille were plunged into crisis last week as Marcelino quit after just seven competitive games in charge.
His departure followed a meeting between fan representatives and the club's hierarchy which reportedly turned nasty, with Marseille saying president Pablo Longoria and several of his senior colleagues were threatened and told to prepare for "war" unless they resigned.
Longoria, who was close to Marcelino, withdrew to consider his position before eventually deciding to remain at the club.
Marseille are eighth in Ligue 1 after losing 4-0 away to Paris Saint-Germain on Sunday.
They are also involved in this season's Europa League and are due to host Premier League club Brighton & Hove Albion in that competition next week.
Gattuso's first match in charge will be against Monaco on Saturday.