Sandy Green began his undergraduate studies at the University of St Andrews in 1942 but they were interrupted by the war during which he worked in Max Newman's group at Bletchley Park operating the Colossus computers.
After finishing his undegraduate degree with First Class Honours in Mathematics he went to Cambridge where he obtained a PhD with Philip Hall in Abstract Algebra and Semigroups. This was followed by a position at the University of Manchester and an appointment to a chair at the University of Sussex in 1963.
He became professor at Warwick in 1965 during its first year where he stayed until his retirement in 1991 when he was made Professor Emeritus.
The London Mathematical Society awarded him the Senior Berwick Prize in 1994 and the De Morgan Medal in 2001. He was made Fellow of the Royal Society in 1987.