The building was part of the later Rockefeller Center expansion (1960s–1970s) dubbed the "XYZ Buildings". Their plans were first drawn in 1963 by the Rockefeller family's architect, Wallace Harrison, of the architectural firm Harrison and Abramovitz. Their letters correspond to their height. 1251 Avenue of the Americas is the "X" Building as it is the tallest at 750 ft (229 m) and 54 stories, and was the first completed, in 1971. The "Y" is 1221 Avenue of the Americas, which was the second tower completed (1973) and is the second in height (674 ft and 51 stories). The "Z" Building, the shortest and the youngest, is 1211 Avenue of the Americas with 45 stories (592 ft).
The building serves as the global headquarters for Australian-born businessman Rupert Murdoch's media companies, 21st Century Fox and News Corp. It served as the world headquarters for the original News Corporation before its 2013 split into 21st Century Fox and (new) News Corp. The building is well known for housing the main studios of the Fox News Channel, part of 21st Century Fox's Fox Entertainment Group. News Corp divisions housed there include Dow Jones & Company, The Wall Street Journal, and the New York Post. Other companies with office there include Annaly Capital Management.