“Zanetti will be the new vice-president of the club, and has signed a two-year contract.
The entire board has also agreed to retire his number four jersey,” Thohir told reporters after a board meeting.
Thohir also announced he would be offering coach Walter Mazzarri a one-year contract extension that will keep him at the club until 2016.
“We’ve discussed a year’s extension on his contract, so we’ll have him for two full years,” he said.
Argentinian Zanetti retired from football at the end of last season after spending 19 years at Inter Milan, during which he won five league titles, scored in a 3-0 1998 UEFA Cup final win over Lazio, and played a key role in the treble-winning 2010 side that produced Inter’s first European Cup title in nearly half a century.
In almost two decades at the club Zanetti made 615 Serie A appearances, by far the most of any foreign player in Italy’s top flight and second only to Paolo Maldini. He also represented his country 145 times.
The 40-year-old said an emotional farewell to fans after Inter’s 4-1 victory over Lazio at the San Siro in May, when he was promised a new role within the club that until Monday had remained unspecified.
Zanetti came on as a 52nd minute substitute during that win, which booked Inter’s place in the Europa League for next season.
Inter finished fifth in Serie A after at campaign that saw frequent protests from fans at Mazzarri’s management and the running of the club by new owner Thohir, the Indonesian businessman who succeeded long-time owner Massimo Moratti as club president in November.
(Reporting by Terry Daley, editing by Stephen Wood)