Harris, reporting to global CEO Pete Pedersen, will be based in New York. Chris Boehlke previously led Grayling's U.S. PR operation as CEO before sliding to a GM role in San Francisco.
Harris was a senior VP at MSL focused on corporate and technology and recently led its corporate tech practice. He also led the United Technologies account.
Previous stints included Ketchum (SVP) and its Access Communications operation (managing director), as well as Peppercom (partner). He came up through Porter Novelli and Broullard Communications.
The hire comes as the firm streamlined its U.S. operations – including the former DutkoGrayling public affairs and lobbying unit -- under the Grayling banner this fall with a renewed focus on tech.
Global CEO Pedersen joined Grayling from Edelman in March on the exit of Michael Murphy.
Harris takes up the post on Jan. 1.