Chris Bown was made managing director after a Â£6m public inquiry published criticisms of the standard of care at Stafford Hospital.
The hospital was renamed the County Hospital, and a new trust set up to replace Mid Staffordshire NHS Trust.
The trust now running the hospital said Mr Bown's job was always "an interim role".
The University Hospitals of North Midlands NHS Trust said its management structure was now being "reviewed".
The health watchdog, the Care Quality Commission, has yet to inspect Stafford County Hospital.
Mr Bown, who was appointed in September, is leaving to become Interim Chief Executive of East Kent Hospitals University NHS Trust.
Mr Bown said: "During my time here I have been hugely impressed with the commitment and expertise of the staff.
"I believe County Hospital and the wider trust have a strong future and I look forward to seeing them both go from strength to strength."
The man brought in to help improve care standards at a Staffordshire hospital is leaving after six months in the job.