Lang was born in Edinburgh and educated at the Royal High School of Edinburgh and the University of Edinburgh where he studied social anthropology, graduating MA in 1968, and PhD in 1974. He lectured in social anthropology for some years at Aarhus University, Denmark. Returning to the United Kingdom, he joined the scientific staff of the Social Science Research Council, where he was latterly Principal Scientific Officer.
After this, he spent four years as Director of Public Affairs for the National Trust, before his appointment as Chief Executive and Deputy Chairman of the British Library from 1991 until 2000. During this period, the British Library made the delayed and over-budget move into its new building at St Pancras.
Lang is a trustee of the Heritage Lottery Fund, a member of the Cultural Commission and was appointed in August 2008 as the Chairman of the Board of Directors of the Royal Scottish National Orchestra.
At St Andrews
Lang succeeded Struther Arnott as Principal and Vice-Chancellor of the University of St Andrews in January 2001. During his first year at St Andrews, Lang was accused of sexual harassment by a member of the University's administrative staff. Shortly before the start of the resulting employment tribunal, the university made an out-of-court settlement.
At an unrelated employment tribunal in 2004, Lang drew on his background in social anthropology to compare an academic department at St Andrews to the Ik tribe of Uganda, who, he said, were noted for their "dishonesty, lying and cheating". (This view of the Ik, due to Colin Turnbull, has been repeatedly criticized.)
Lang was accused of hypocrisy by the St Andrews student newspaper The Saint for promoting the University's environmental policy by asking other members of the university not to use cars, while continuing to use his Jaguar to make the 1.1 mile journey to his office.
On 9 March 2006 it was announced that he was to be inducted as a Fellow of the Royal Society of Edinburgh.
Lang, upon retirement as Principal and Vice-Chancellor of the University of St Andrews, was succeeded by Louise Richardson. He demited office on 31 December 2008.
- University of St Andrews: The Principal - Dr Brian Lang 
- National Heritage Memorial Fund - Brian Lang 
- The London Gazette: . 11 June 2016.
- Peterkin, Tom: "Prince's university head denies sex case claim", The Telegraph, 20 August 2001 
- Urquhart, Frank: "University settles sexual harassment case minutes before hearing", The Scotsman, 21 May 2002 Archived May 22, 2005, at the Wayback Machine.
- "Lecturers compared to lying tribesmen", The Times, 17 January 2004 
- Heine, Bernd, The Mountain People: Some Notes on the Ik of North-Eastern Uganda. Africa: Journal of the International African Institute, Vol. 55, No. 1, 1985, pp. 3–16.
- Knight, John, 'The Mountain People' as tribal mirror. Anthropology Today, Vol. 10, No. 6, December 1994.
- Stokeld, Nick: "I want to Buy Brian a Bike", The Saint, 10 Nov 2007.
Professor Struther Arnott
Principal of the University of St Andrews
January 2001–December 2008
Professor Louise Richardson