He rapidly acquired a large practice, being, according to Anthony à Wood, 'much frequented by clients for his wonderful and pregnant knowledge of the common law.'
A career thus brilliantly commenced was cut short by his untimely death, which took place at Lincoln's Inn on 23 Nov. 1693 .
His death was lamented in some elegant Latin alcaics by his friend, G. Adams (Musæ Anglicanæ, ii.
Harrington was the author of a poem in Latin hexameter verse on the death of Charles II, which displays considerable command of the metre (ib.
Stradling,' London, 1692, 8vo, and contributed the preface to the first edition of Athenæ Oxonienses, and the introduction to the second volume (1st ed.)