London made the announcement Sunday night on Twitter and told ESPN.com that Tennessee recently offered him a roster spot.
London asked for his release from Michigan State in February, and he is on track to graduate from the school in May. London rushed for 304 yards on 83 carries last season with the Spartans in a reserve role.
"I felt like Tennessee was a great fit," London told ESPN.com. "I like where they're heading and what they're trying to do with the program. They want to bring Tennessee back. It was a good situation for me knowing I could contribute right away."
London said Tennessee was the first school that contacted Michigan State for his release papers after he announced he would be leaving the Spartans. He also had been in communication with USC, Oregon, Georgia and Louisville.
The 6-foot-1, 218-pound London, a native of Little Rock, Arkansas, expects Tennessee to run a physical offense under new coach Jeremy Pruitt and offensive coordinator Tyson Helton.
"They're going to need a running back who can carry the load, and I can do that," London said. "I just want to be a playmaker, just work hard and be the life of the party, have everybody excited and work hard."