William R. Sweeney Jr. has left his position as deputy chairman of the Democratic National Committee to form Washington Resources and Strategy Inc., a public relations firm specializing in government relations and political consulting. Sweeney was deputy chairman of the DNC from 1981 to the present, and, from 1977 to 1981, was executive director of the Democratic Congressional Campaign Committee.

Henry Fairlie, a freelance writer and contributor to The New Republic, has joined Washingtonian magazine as editor-at-large.

Gray & Co. has promoted Stephen M. Johnson from vice president to senior vice president of the Washington public relations firm. Johnson is a former reporter for The Boston Globe, The Des Moines Register and The Washington Star, and was media relations director of the National Association of Manufacturers until 1983. John J. Cergol Jr., former communications manager for the Food Marketing Institute, has joined Gray as an account executive.

Stan Felder, formerly editor of The Prince George's Journal newspaper, has formed The Stan Felder Group, a communications consulting firm that will be affiliated with Richard Scott & Associates in Greenbelt.

MCI Telecommunications Corp. has named Daniel F. Akerson president of its Southeast division. Akerson, previously executive vice president of MCI International, will be based in the company's Atlanta office.

The Chesapeake & Potomac Telephone Cos. has appointed Graham K. Ragland assistant vice president in charge of its regulatory planning and external affairs department in Washington. Ragland, formerly a division manager, succeeds Osborne O. Ashworth Jr., who has retired.