He was an outstanding student, gaining numerous distinctions in mathematics, physics and natural science, as well as law.
His reputation as a barrister was mixed: he was considered too nervous and retiring to be a good advocate, and disliked the rough-and-tumble of Court practice but hard work and academic brilliance compensated for this.
Naish is credited with having advised that magistrates in dealing with the Irish National Land League should rely on a fourteenth-century statute, the Justices of the Peace Act 1361 (34 Edw.
He stood for the House of Commons at Mallow as the Government candidate in 1883, but in the fraught political atmosphere which followed the Phoenix Park murders, he was crushingly defeated by William O'Brien.
[3] Naish's health failed when he was still in his late forties: he travelled to the Continent in hope of a cure, but died at the German spa town of Bad Ems on 17 August 1890, two days after his forty-ninth birthday, and was buried there.