Dr Evan Harris was educated at Blue Coat Secondary School, Liverpool. After a year at Harvard High School in North Hollywood, he went to Wadham College, Oxford in 1985 to study physiological sciences (BA), and then medicine at Oxford University Clinical School from where he qualified as a doctor in 1991.He trained in emergency hospital medicine in Liverpool and at the Oxford Radcliffe Hospital. In 1994 he took up an honorary public health registrar post with the Regional Health Authority.

Following his election in 1997, he was a junior health spokesman, then spokesman on Higher Education and Women's Issues. Following his re-election in 2001 he was appointed the Liberal Democrat Shadow Secretary of State for Health.

Evan has a particular interest in medical ethics, previously serving on Oxfordshire Health Authority's Research Ethics Committee, and since 1999 has been an elected member of the British Medical Association's Medical Ethics Committee. He has worked as a trained HIV/AIDS counsellor in Oxford.