Willie was the oldest son born into an Anglo-Irish family, at 21 Westland Row, Dublin, to Sir William Wilde and his wife Jane Francesca Wilde (née Elgee) (her pseudonym being 'Speranza'). Their second son, Oscar, was born in the same house in 1854. Jane Wilde was a successful writer, being a poet for the revolutionary Young Irelanders in 1848 and a lifelong Irish nationalist. Sir William was Ireland's leading Oto-Ophthalmologic (ear and eye) surgeon and was knighted in 1864 for his services to medicine. William also wrote books on archaeology and folklore. He was a renowned philanthropist, and his dispensary for the care of the city's poor, in Lincoln Place at the rear of Trinity College, Dublin, was the forerunner of the Dublin Eye and Ear Hospital, now located at Adelaide Road.
In June 1855, the family moved to 1 Merrion Square in a fashionable residential area, where Wilde's sister, Isola, was born in 1856. Here, Lady Wilde held a regular Saturday afternoon salon with guests including Sheridan le Fanu, Samuel Lever, George Petrie, Isaac Butt and Samuel Ferguson.
In February 1864, Willie and Oscar were sent to board at the Portora Royal School at Enniskillen in Ulster, where Willie became known for his good-humour and friendliness, later being described by a classmate as "clever, erratic and full of vitality". Oscar became known to his school fellows by the nickname ‘Grey Crow’, which he disliked, while Willie was ‘Blue Blood’. Willie was "an accomplished pianist and an artist of little talent’ Oscar Wilde later recalled that the headmaster, Dr Steele, had told him that “If I went on studying as I had been during the last year I might yet do as well as my brother Willie, and be an honour to the school and everyone connected with it.”
Willie was already a student at Trinity College, Dublin when Oscar joined him in 1871, the two sharing rooms during their second and third years there. In 1876 'Willie' published several of his poems in the College magazine Kottabos, which he also edited.
After graduating from Trinity College Willie Wilde studied Law and was called to the Irish Bar but never actually practised Law. On the death of his father in 1876 he and Lady Wilde moved to London in early 1879, where he became a journalist, serving as drama critic for Punch and Vanity Fair, as well as being the leader writer for The Daily Telegraph and the editor of Christmas numbers of several magazines. Willie was a regular guest at London's 'Fielding Club', which during its short life opened its doors at eight o’clock in the evening and remained open all night. The club was famous for its grills, its brandy and its Pol Roger ‘74 at any time, though its tripe and onions on Saturdays were an especial draw. One member listed Willie among those who were ‘constant guests’ on Saturdays, along with Henry Irving, Herbert Beerbohm Tree, J. Comyns Carr, Edward Dicey, Carlo Pellegrini, Frederic Clay and Oscar Wilde himself.
Ralph Nevill, the son of Lady Dorothy Nevill, said of Willie Wilde:
"Willie Wilde was a clever journalist who, had he been less careless in his habits, might have achieved considerable success. As it was, a number of the articles which he wrote for the Daily Telegraph were little short of brilliant, while as a talker, few could equal him. He was, however, his own enemy, and could not resist the attractions of the moment or settle down long to regular work – in truth, though not very old in years, he belonged to the now almost extinct school of journalists which, taking ‘sufficient is the day for the evil there of’ as their motto, never gave a thought to the future (or anything else) if they happened to have a few pounds in their pockets."
By the time of Oscar's marriage in 1884 Willie was seriously in debt and drinking heavily. On 4 October 1891, aged 39, Willie married a wealthy widow, Mrs. Frank Leslie, (1836–1914), the owner of the Frank Leslie Publishing Co. in New York. She was initially attracted by Willie's humour and wit; however, he spent much of his time in New York's fashionable Lotos Club drinking, gossiping about London Society and reciting parodies of his brother's poems, which strongly suggests that he was jealous of Oscar's success. The marriage was short-lived, Mrs Leslie starting divorce proceedings within a year of the marriage on the grounds of Willie's drunkenness and adultery. They were finally divorced on 10 June 1893. It was Mrs Leslie who approached Oscar Wilde with the idea that he give a series of lectures in the United States.
On his return to London early in 1892, Willie found that Oscar was the toast of the town for his successful play Lady Windermere's Fan. It is believed that Willie wrote the hostile review for the play which was published, unsigned, in Vanity Fair on 27 February 1892, for which magazine he had previously been a theatre reviewer. "The play", he wrote, was "brilliantly unoriginal," but the dialogue was "uniformly bright, graceful, and flowing." After describing the plot and pointing out some of its banalities, he went on to describe it as "an undeniably clever piece of work; and even though it has its weaknesses, it reflects credit on its author... It is emphatically a play to see." Oscar, recognising the hand of his brother behind the anonymous review, was by then writing A Woman of No Importance, in which one character says: "After a good dinner, one can forgive anybody, even one's own relations."
Willie Wilde by now being in serious financial difficulties, Oscar began giving him money, but bad feeling between the brothers heightened when Oscar discovered that Willie was constantly pestering their far from well-off mother for money. Oscar once said of Willie ‘He sponges on everyone but himself’. Max Beerbohm saw them as mirror images, and this is how he portrayed them in his caricatures. In a letter to the painter William Rothenstein, Beerbohm wrote, "...did I tell you that I saw a good deal of [Oscar's] brother Willie at Broadstairs? Quel monstre! Dark, oily, suspect yet awfully like Oscar: he has Oscar's coy, carnal smile & fatuous giggle & not a little of Oscar's esprit. But he is awful – a veritable tragedy of family-likeness".
Beerbohm later wrote:
"My sister Constance came home one day and summoned my mother and me; she was quivering to tell us what had happened. She knew in advance it was the sort of thing my mother would adore. Well, Constance had been walking along the street and met Willie Wilde – Oscar’s brother. In one hand, he was carrying a huge leg of mutton by the narrow part; with his free hand he swept off his hat and bent over double in a grand, ceremonial bow. There was something so grotesquely funny in the way he did it, conveying both the mutton and the bow. We decided it was a first class thing."
Willie married Sophie Lily Lees (1859–1922) in January 1894, with whom he had been living. She has been described as "an emotional woman with a tendency to early panic... she believed (incorrectly) that she was pregnant" She tried to induce an abortion by taking a powder. The marriage caused further distress to Lady Wilde when the couple moved in with her. She wrote to Oscar on 4 February 1894, telling him of the marriage: "Miss Lees has but £50 a year and this just dresses her. She can give nothing to the house and Willie is always in a state of utter poverty. So all is left upon me". Willie and Lily had their only child, Dorothy Ierne Wilde, in July 1895.
Lady Wilde wrote Oscar a lengthy letter asking him to be reconciled with Willie, who, she said, was "sickly and extravagant." She was "miserable at the present position of [her] two sons" and "at the general belief that you hate your brother." She then asks Oscar to hold out his hand to Willie, a request she repeats several times in the letter. "Come then & offer him yr. hand in good faith – & begin a new course of action".
Following Oscar's arrest and first trial in April 1895, Willie claimed that he gave his brother shelter when he was unable to find rooms in London. Willie said that Oscar "fell down on my threshold like a wounded stag". Standing by his brother, Willie wrote to Bram Stoker, "Bram, my friend, poor Oscar was not as bad as people thought him. He was led astray by his Vanity – & conceit, & he was so 'got at' that he was weak enough to be guilty – of indiscretions and follies – that is all.... I believe this thing will help to purify him body & soul".
Willie did not meet Oscar when he was released from prison in 1897. On 13 March 1899 Willie died aged 46 at 9, Cheltenham Terrace in Chelsea from complications related to his alcoholism. After Robert Ross wrote to Oscar in France informing him of Willie's death, Oscar wrote "I suppose it had been expected for some time.... Between him and me there had been, as you know, wide chasms for many years. Requiescat in Pace".
His widow married in 1900 with the Dutch born, London based translator Alexander Teixeira de Mattos (1865-1921).
- Literary Encyclopedia – Oscar Wilde
- Quoted in James Holroyd's 'Brother to Oscar', Blackwood's Magazine, March 1974
- Burke’s Irish Family Records (London: Burke’s Peerage 1976) p.1217
-  Willie Wilde on the Oscar Wilde website
- Sir Vincent Corbett, K.C.V.O.: Reminiscences, Autobiographical and Diplomatic. London: Hodder & Stoughton n.d (preface dated July 1927) p.38
- Ralph Nevill, 'The World of Fashion 1837–1922' (London: Methuen: 1923 p.70
- The New York Times 11 June 1893
- Madeleine B. Stern, Purple Passage: The Life of Mrs. Frank Leslie (1953)
- 'Vanity Fair' review, 27 February 1892
- 'Max and Will: Max Beerbohm and William Rothenstein, Their Friendship and Letters, 1893–1945' Edited, with Introductions and Notes by Mary M. Lago and Karl Beckson. London: (1975) p.21
- Max Beerbohm, quoted in S.N. Behrman: Conversations with Max. London: Hamish Hamilton 1960 p.38
- Kevin O'Brien, "Lily Wilde and Oscar's Fur Coat," Journal of the Eighteen Nineties Society 21 (1994)
- Karl Beckson, "The Importance of Being Angry: The Mutual Antagonism of Oscar and Willie Wilde," Blood Brothers: Siblings as Writers, ed. Norman Kiell New York: International University Press (1983)
- Barbara Belford, Bram Stoker: A Biography of the Author of Dracula (1996)
- 'The Times' 15 March 1899
- Belford, Barbara. Oscar Wilde: A Certain Genius. New York: Random, 2000