He had a grammar school education and gave up an early career in accountancy to join the Royal Ulster Constabulary in 1950.
[1] After joining the RUC, he was posted in various parts of western Northern Ireland, including Eglinton, Coalisland and Strabane, before sitting his sergeant's examinations.
An anonymous former interrogator has claimed that "The new chief constable was completely against any mistreatment of prisoners whatsoever...we started to detect a change .... straight away."
In 1987 he met Sylvia Paisley who had written an academic paper critical of Hermon's conduct in an employment case brought by female RUC officers.
[1] After his death, his widow, Lady Hermon, was, from 2005 to 2010, the sole Ulster Unionist Party (UUP) Member of Parliament.