The 6-foot-11 Walker, who was ranked 12th in the class of 2013 by ESPN.com, has been in limbo since being admitted to Florida in December.
Walker sat out while the NCAA investigated his amateur status.
The NCAA said in a statement that Walker received preferential treatment from five people, including two agents. Walker will be required to donate the $270 he received from the agents to a charity and serve 80 hours of community service for the remaining benefits received.
The NCAA also found that Walker, while a prospect, received free cellphones and service, airfare, lodging, meals and apparel. Individuals close to Walker received free airfare and lodging for nine trips -- including eight associated with AAU competitions.
"We're glad there's a resolution for everyone involved, especially for Chris," Gators coach Billy Donovan said in a statement. "We appreciate everyone's participation in this process and are ready to move forward."
Walker is extremely talented and could wind up being a lottery pick, but Donovan has cautioned against expecting too much from the long and athletic big man.
The No. 3 Gators (17-2, 6-0 SEC) already have veteran big men Patric Young and Will Yeguete. Expect Walker to fill a role as a defensive-minded shot-blocker who can come off the bench and add depth to the frontcourt.
The Associated Press contributed to this report.