Simon Goodley will leave next month to join the corporate and financial agency.
At the firm he will link up with former Telegraph columnist Charlie Methven and former British Airways comms chief David Burnside.
New Century clients include the Tchenguiz brothers, Vincent and Robert, and Arsenal Football Club.
'When I decided to move into PR, my priorities were to work alongside colleagues I respect,' Goodley said yesterday. 'In recent years I have dealt with David and Charlie on a host of big stories, so have first-hand experience of New Century.'