Malcolm Cameron Lyons was born in India in 1929. He was of mixed Scottish and Irish ancestry, the son of a Church of Scotland minister who died when Malcolm was very young. He was brought up by his mother, and the family (he had a sister) lived in St Andrews. He was educated at Fettes College in Edinburgh and awarded at the age of seventeen a major scholarship in Classics at Pembroke College, Cambridge. His academic performance there was outstanding, and he gained a first-class degree in the Classics Tripos and was awarded university prizes. On leaving Cambridge, he did his National Service in the RAF from 1949 to 1951. He then returned to Pembroke where he studied for a second degree, this time in Arabic and Persian. After two years he gained yet another first-class degree. He began a PhD, became a University Assistant Lecturer and a Fellow of Pembroke in 1956; he was awarded a PhD in 1957. He spent a year on sabbatical leave in Lebanon, accompanied by his Swiss wife Ursula whom he had just recently married. She had graduated from St Andrews University with a degree in Arabic.

Once back in Pembroke College, where he was destined to stay for the rest of his life, it soon became clear that Malcolm was an especially gifted Arabist. Indeed, Arthur J. Arberry, the Sir Thomas Adams's Professor of Arabic at that time, who was also a Fellow of Pembroke, already indicated that he thought that Malcolm Lyons would eventually succeed him in this ancient and prestigious Chair. Malcolm enjoyed working for a long time in Pembroke as Admissions Tutor. He served as a University Lecturer (1959–84) and a Reader (1984–85). He then held the Sir Thomas Adams's Chair from 1985 until his retirement in 1996. He became a Life Fellow of Pembroke in that year. He served as a Trustee of the Gibb Memorial from 1963 to 1997, attending meetings quite regularly and playing an active role in the Trust's business. His book, Identification and Identity in Classical Arabic Poetry, was published by the Trust in 1999.