The sport, which featured in the ancient Olympics and in every modern Games apart from 1900, had been surprisingly taken off the Games in February as the IOC looked to refresh its sports programme.
Much of the credit for the victory will go to wrestling federation (FILA) president Nenad Lalovic, who took over in February just after the sport's Olympic exit and immediately overhauled wrestling's rules, administration, gender equity, and operations.
Loading article content
Lalovic said: "Our modernisation will not stop now. We will continue to strive to be the best partner to the Olympic Movement that we can be."
Wrestling got 49 of 95 votes, with baseball/softball earning 24 and squash landing 22 votes from the IOC members.
Meanwhile, the prime minister of Japan, Shinzo Abe, praised Tokyo's successful bid to host the 2020 Olympic Games - beating Istanbul in a head-to-head vote - as an opportunity to showcase his country's resurgence after a devastating earthquake, but stressed the city must work to win the world's trust.
"The real Games have only just started for Tokyo," Abe said. "Let us make . . . efforts to win the trust and confidence of people in the world so that the decision to choose Tokyo today will be remembered as the right one."
Tokyo won the right to organise the Games despite concerns over the leaking Fukushima nuclear plant 140 miles from the Japanese capital.
The IOC vindicated the Japanese capital for a strategy which saw them highlight their solid finances and strong track record of delivering on promises. The next summer Olympics will be hosted by Rio de Janeiro in 2016. The preparations for that Games have been plagued by delays and complications, and a decision for Tokyo 2020 is a return to safer waters for the Olympic movement.