Jonathan trained at the Welsh National School of Medicine in Cardiff, qualifying in 1979. After a year as a research SHO in geriatric medicine, he moved to Merthyr Tydfil in the South Wales Valleys to train for General Practice. He was a GP in Merthyr from 1984 to 2015 when he retired from active clinical work.
He has been the Chair of the Bro Taf Primary Care Audit Group from its inception in 1996. He was a Senior Clinical Adviser for Primary Care Quality, a division of Public Health Wales from 2000 to 2016 advising Government about performance and Outcome Measures. He has been External Professor of Primary Care at the School of Care Sciences, University of South Wales since October 1997 and has worked with WIHSC on many projects.
His research interests include postnatal depression, quality and clinical effectiveness (with special reference to diabetes and coronary heart disease), primary care development strategies (particularly in communities experiencing socio-economic deprivation), the consultation as a cross-cultural experience and multi-disciplinary learning in primary care.