Dr Juniper qualified from the University of London in 1989. After working in junior posts in London and Leeds and becoming a member of the Royal College of Physicians he was appointed as registrar to the Nuffield department of Medicine in Oxford in 1993. In Oxford he underwent training in general, respiratory and intensive care medicine. He was appointed as Consultant in Respiratory and Intensive Care Medicine in Swindon in 2000.
During his consultant career in Swindon he has put in place a hospital wide system to ensure high quality of care for acutely ill patients. He has established a ward based ventilation service. He has also worked as Associate Medical Director from 2006-2009.
His clinical interests include sleep medicine which has led to the establishment of a sleep service in Swindon. In addition he is a key member of the lung cancer team and runs outpatient services in general respiratory medicine.