The former Sweden international has returned to Italy in a bid to revive the fortunes of a struggling Milan team who are languishing in 11th place.
During his first stint at the San Siro, he finished his two seasons at the club as the top scorer, bagging 21 goals in all competitions and led the club to their last Scudetto to-date in the 2010/11 season.
By the end of his second season, he left the club for Paris Saint-Germain having led the Rossoneri to a second-place finish with 28 league goals to his name.
According to Sport Italia, the veteran striker is set to earn €3.5m (R55.6m) in addition to €500 000 (R7.8m) in bonuses over the next six months.
This deal could be extended by a year if the former LA Galaxy star features in half of Milan's matches from now until the end of the season.
With the deal extension, his earnings would automatically rise to €6m (R94.6m) plus add-ons that will reach €4m (R63m) by the end of 2020-2021 season, which will see Ibrahimovic reach his 40th birthday.