[2] Owing to a medical condition, he was considered unfit for military service at the beginning of the Second World War, so he continued his studies and began his legal career during those years.
[2] Johnston was admitted to the Faculty of Advocates in 1942 and quickly established a substantial and varied practice which he developed during the forties and fifties.
[3] In 1959, he unsuccessfully contested the Stirling and Falkirk burghs constituency in the general election as a Unionist candidate.
He misdirected the jury in the Ice Cream Van murders trial of Campbell and Steele, who were later freed on appeal.
[2] The government accepted most of the recommendations; in 1993, legislation was introduced[4] on the automatic early release of short-term prisoners, subject to recall if reoffending, and a revised parole system.