Guardian News and Media has recruited a former media agency executive to be chief exec of Guardian US.
Eamonn Store was formerly president, agency development, of MEC.
GNM said in a statement: "Store will join the Guardian on the same day as incoming US editor-in-chief, Katharine Viner, and together they will shape the vision and direction of the next stage of development of the US operation, building on the success enjoyed since launch in 2011.
"As CEO, Eamonn will take charge of the overall business and commercial offerings for the Guardian's US operations and will drive digital innovation across all platforms."
It follows news that GNM is opening a West Coast office in the US in addition to the New York operation.
GNM deputy chief executive David Pemsel said that Store "brings a wealth of experience of the US and UK media markets and a strong understanding of our brand positioning and opportunities for growth in the US. His arrival, on the same day as incoming editor-in-chief, Katharine Viner, marks the start of a new phase for the hugely admired and respected US operation, and together they will drive ongoing development of the Guardian's US offering as it reaches an ever-wider audience across America."
Viner said: "His invaluable industry experience, deep understanding of the Guardian and passion for our innovative digital journalism make him a terrific partner to deliver on our ambitious plans. I can't wait to get going and see what we can achieve together."
Store and Viner will take up their new jobs on 2 September.