Professor Sagar was educated at Manchester Grammar School
He studied medicine on an Open Scholarship at the University of Oxford
He undertook clinical and research fellowships in Paris, France and Boston, USA.
He was Consultant Neurologist at the Royal Hallamshire Hospital, Sheffield from 1984 to 1992 and Professor and Head of Department of Clinical Neurology, University of Sheffield, from 1992 to 1999
He now works full-time in private practice at Thornbury Hospital, Sheffield
His particular interests within clinical neurology are movement disorders, particularly Parkinson's disease, and disorders of memory and cognition.