Lever was born in Dublin, the second son of James Lever, an architect and builder, and was educated in private schools. He is said to have been a ringleader in all kinds of trouble and to have behaved like a boy destined for the navy in one of Captain Marryat's novels. His escapades at Trinity College, Dublin (1823 - 1828), where he took the degree in medicine in 1831, are drawn on for the plots of some of his novels. The inimitable Frank Webber in Charles O'Malley (spiritual ancestor of Foker and Mr Bouncer) was a college friend, Robert Boyle, later on an Irish parson. Lever and Boyle sang ballads of their own composing in the streets of Dublin, after the manner of Robert Fergusson or Oliver Goldsmith, filled their caps with coppers and played many other pranks embellished in the pages of O'Malley, Con Cregan and Lord Kilgobbin. Before seriously embarking upon the medical studies for which he was designed, Lever visited Canada as an unqualified surgeon on an emigrant ship, and has drawn upon some of his experiences in Con Cregan, Arthur O'Leary and Roland Cashel. Arrived in Canada he plunged into the backwoods, was affiliated to a tribe of Native Americans and had to escape at the risk of his life, like his own Bagenal Daly.