Born on 24 May 1881, the son of a Wesleyan schoolmaster, he was educated at King Edward VI's School and Birmingham University, where he took his BSc in 1901, with an Education Diploma at Westminster Training College. After teaching Chemistry and Physics, he joined the staff of Westminster College, obtaining a London MA in 1916. Unfit on health grounds for military service, his wartime service included being vice-principal of the college, running the Petersham Russell School, teaching science at Tiffins School, and acting secretary of the Richmond Education Committee.
In 1921 he was appointed Headmaster of Truro School. During his term of office, the school was greatly extended with the building of the chapel, a science block and junior boarding houses, and the acquisition of Treliske as a preparatory school. In 1925 he received a doctorate in Science from London University as a result of 12 years' research in experimental psychology and theoretical chemistry, and was appointed as the Senate's representative to the Board of Governors of the University College of the South West (now Exeter University). As a prominent Freemason he was a founder and fifth Master of the Epworth Lodge, London and a founder of the Truro School Lodge and its first Worshipful Master in 1936. In 1940 he was appointed Provincial Grand Chaplain of the Province of Kent.
Retiring in 1946, he was ordained as an Anglican priest and in1950 moved to Dover, where he died on 6 August 1961.
One of his sons,Thomas S. Magson, followed his father into a career in education and was headmaster of several secondary schools, before becoming in retirement, like his father, an ordained clergyman.