Schofield has served as Prescott's special adviser on media and as spokesperson for his office since 2002.
He will join Bell Pottinger's 'collective' of consultants who work across the agency's different practices. Schofield will oversee issues management.
A former BBC producer for Breakfast With Frost, Schofield said he was looking forward to aiding clients that have complicated stakeholder comms requirements.
'It's good to join an agency as PR is going through a period of growth,' he said.
Prior to the Office of the Deputy Prime Minister, Schofield was media director for the Queen's Golden Jubilee media centre, handling coverage of plans for the 2002 celebrations.
As Prescott's aide, Schofield handled media coverage around a range of issues, including the lengthy fire service dispute.
At Bell Pottinger, Schofield will report to Tim Ryan, who heads the collective, formed this year as part of a restructure of the group (PRWeek, 17 March).
A replacement for Schofield has yet to be found.