Born in Great Yarmouth, Alderson was the eldest son of Robert (died 1833), a barrister and recorder, and Elizabeth "née" Hurry who died in 1791. Alderson suffered an unstable childhood, variously living with relatives, unhappily attending Charterhouse School but, more positively, being tutored by Edward Maltby. He was an able student of mathematics and classics at Gonville and Caius College, Cambridge, about to take exams he heard of the sad death of his sister Isabella. A year later in 1809 he graduated as senior wrangler, First Smith's prize, was First Medallist, and Chancellor's Gold Medallist. During free time he became an ardent debater and avid reader; winning Middle Bachelors, and the Latin Prize for "Comparison of Ancient Dialogues with Modern". In his finals year he also won the Members Prize, and Senior Bachelors Prize. He was consequently elected fellow.