Keith qualified as a social worker in 1974. He worked in area teams and hospitals before leaving in 1988 to read for the Bar. He was a barrister between 1990 and 2012. He completed his LLM in Social Welfare Law in 2008

For 20 years he was a fee paid judge in what is now the Social Entitlement Chamber of the Tribunals Service and he has been a fee paid judge in the Health and Social Care Chamber (mental health tribunals) for 10 years, sitting in the Midlands.