He acted as both the President and CEO Irwin Stayed with MediaVest Worldwide for 6 years until September 1999 when he joined WPP plc as the Chairman and CEO of MindShare Worldwide .
He acted as both the President and CEO . 
 Irwin stayed with MediaVest Worldwide for 6 years until September 1999 when he joined WPP plc as the Chairman and CEO of MindShare Worldwide .