The animal, named Romeo by staff, is thought to have entered the tower at London Bridge through the central stairwell.
It survived by eating scraps of food left by builders working on the site.
The fox was captured and taken to Riverside Animal Centre in Wallington where it was fed and given a check-up.
Ted Burden, the centre’s founder, said: “We explained to him that if foxes were meant to be 72 storeys off the ground, they would have evolved wings.
“We think he got the message and, as we released him back on to the streets of Bermondsey shortly after midnight on Sunday, he glanced at the Shard and then trotted off in the other direction.”
Barrie Hargrove, cabinet member for transport, environment and recycling at Southwark Council, said: “Romeo has certainly been on a bit of a jaunt and proved rather elusive.
“But I’m glad our pest control officers were able to help out.
“He’s obviously a resourceful little chap, but I’m sure he’s glad the adventure is over and hopefully he’ll steer well clear of skyscrapers in the future.”