He began an academic career at Selwyn College, Cambridge. He then moved to industry and worked first at VG Instruments and later Oxford Instruments. He was chairman of Oxford Instruments from 1991 until his retirement in 1999.[citation needed]
In 2005 Williams became the fifth chancellor of the University of Leicester. He was also appointed patron for research at Marie Curie Cancer Care. He retired from this position in 2010. In 2015 Williams was appointed chairman of Kromek, an innovative British tech company making detectors for the medical, security and nuclear sectors.[5]
^"Birthday's today". The Telegraph. 22 March 2012. Archived from the original on 22 March 2012. Retrieved 20 April 2014. Sir Peter Williams, Chancellor, University of Leicester, 2005–10; Master of St Catherine's College, Oxford, 2000–2002, 67