Lever is the second son of James Lever, an architect and builder, and is educated in private schools. His escapades at Trinity College, Dublin (1823–1828), where he earns a degree in medicine in 1831, are drawn on for the plots of some of his novels. The character Frank Webber in the novel Charles O’Malley is based on a college friend, Robert Boyle, who later becomes a clergyman. He and Boyle earn pocket-money singing ballads of their own composing in the streets of Dublin and play many other pranks which he embellishes in the novels Charles O’Malley, Con Cregan and Lord Kilgobbin.
Before seriously embarking upon his medical studies, Lever visits Canada as an unqualified surgeon on an emigrant ship. Arriving in Canada, he journeys into the backwoods, where he is affiliated to a tribe of Native Americans but has to flee because his life is in danger, as later his character Bagenal Daly does in his novel The Knight of Gwynne.
Back in Europe, Lever pretends he is a student from the University of Göttingen and travels to the University of Jena and then to Vienna. He loves German student life and several of his songs, such as “The Pope He Loved a Merry Life,” are based on student-song models. His medical degree earns him an appointment to the Board of Health in County Clare and then as a dispensary doctor in Portstewart, County Londonderry, but his conduct as a country doctor earns him the censure of the authorities.
In 1833 Lever marries his first love, Catherine Baker, and in February 1837, after varied experiences, he begins publishing The Confessions of Harry Lorrequer in the recently established Dublin University Magazine. Before Harry Lorrequer appears in volume form (1839), he has settled on the strength of a slight diplomatic connection as a fashionable physician in Brussels.
In 1842 Lever returns to Dublin to edit the Dublin University Magazine, and gathers round him a typical coterie of Irish wits. In June 1842 he welcomes William Makepeace Thackeray, the author of The Snob Papers, to Templeogue, four miles southwest of Dublin, on his Irish tour. The O’Donoghue and Arthur O’Leary (1845) make his native land an impossible place for Lever to continue in. Thackeray suggests London, but Lever requires a new field of literary observation and anecdote. His creative inspiration exhausted, he decides to renew it on the continent. In 1845 he resigns his editorship and goes back to Brussels, whence he starts upon an unlimited tour of central Europe in a family coach. Now and again he halts for a few months, and entertains to the limit of his resources in some ducal castle or other which he hires for an off season.
Depressed in spirit as Lever is, his wit is unextinguished. He is still the delight of the salons with his stories, and in 1867, after a few years’ experience of a similar kind at La Spezia, he is cheered by a letter from Lord Derby offering him the more lucrative consulship of Trieste. The $600 annual salary does not atone to Lever for the lassitude of prolonged exile. Trieste, at first “all that I could desire,” became with characteristic abruptness “detestable and damnable.”
Lever’s depression, partly due to incipient heart disease, partly to the growing conviction that he is the victim of literary and critical conspiracy, is confirmed by the death of his wife on April 23, 1870, to whom he is tenderly attached. He visits Ireland in the following year and seems alternately in high and low spirits. Death had already given him one or two runaway knocks, and, after his return to Trieste, he fails gradually, dying suddenly, however, and almost painlessly, from heart failure on June 1, 1872 at his home, Villa Gasteiger. His daughters, one of whom, Sydney, is believed to have been the real author of A Rent in a Cloud (1869), are well provided for.