He was born in Comber, County Down, second son of John Andrews, a wealthy flax spinner, and Sarah, daughter of William and Sarah Drennan; his elder brother Thomas, the father of three eminent sons, inherited the family business.
He practised mainly on the North-Eastern Circuit, where his skill in persuading juries of the merits of his client's case became renowned.
Maurice Healy quotes the remark: "Once Andrews has stated his client's case to the jury, the only uncertain thing is how great the award of damages will be".
Maurice Healy's portrayal of Andrews in The Old Munster Circuit is valuable but largely second-hand, since he apparently only met him once.
He describes Andrews as a quiet, precise, modest and courteous man, diligent, upright, and with a great fund of legal knowledge.