LOS ANGELES – Walt Disney World has a new president: George Kalogridis will take over the top job at the Florida resort on Feb. 1. Disney Made the announcement on Wednesday as part of a broader shuffling of management at its $12.9 billion parks and resorts division.

The job is enormous. Disney World, which attracts an estimated 30 million people a year, sprawls over 40 square miles and includes six theme parks, 25 Disney-owned hotels and 81 holes of golf. About 64,000 employees work at the complex.

Mr. Kalogridis, who has been running Disneyland Resort in California, will also be responsible for overseeing the construction of an “Avatar”-themed land in Orlando, estimated to cost $400 million, and implementing a sweeping technology upgrade anchored around a vacation management service called MyMagic+.

Michael Colglazier, who has been running Disney’s Animal Kingdom park, which is part of Disney World, will take over for Mr. Kalogridis in California. Both men will report to Meg Crofton, president of Walt Disney Parks and Resorts Operations for the United States and France; Ms. Crofton previously also served as Disney World’s direct chief, but those duties will now fall to Mr. Kalogridis.

Disney also announced a series of executive changes in marketing and its time share Disney Vacation Club business.