Kevin O'Brien trained as a dentist at Manchester and qualified in 1979 and worked for four years in general dental practice in Middleton and Chorlton. He then returned to the hospital service and trained as an Orthodontist in Manchester. He then returned to Manchester and completed the Manchester orthodontic specialty training programme in 1986. Following this he was appointed as a Medical Research Council Research Fellow and carried out a Ph.D research programme into the effectiveness of orthodontic treatment. In 1991 he spent a sabbatical year in Pittsburgh USA as associate professor. He was made Professor of Orthodontics in November 1995. He was Head of the School of Dentistry from 2004-2007 and was Faculty Associate Dean for Learning and Teaching 2007-11. He was Chair of the General Dental Council from 2011 to 2013.