Byrne, John Francis (1880–1960), journalist, writer, and university friend of James Joyce (qv), was born 11 February 1880 at 25 East Essex Street, Dublin, youngest child of Mathew Byrne (d. 1883), a shopkeeper, and Bridget Byrne (née Byrne) (d. 1893). His father farmed in Co. Wicklow till a fire destroyed one of his properties in the mid 1870s, whereupon he moved to Dublin and entered the dairy and general provisions business. Reared by older sisters and cousins after his mother's death, Byrne was educated by the Carmelites in Clarendon Street (1884–8) and Lower Dominick Street (1888–92), and by the Jesuits at Belvedere College (1892–5). Months after passing the intermediate examinations, he passed the matriculation examination of the RUI, and entered University College in autumn 1895. A sceptic from an early age, he declined an invitation to enter the Jesuit novitiate. Handsome, clever, and athletic, he was a prize-winning champion at chess; he also excelled at handball, and enjoyed long, vigorous rambles in the Dublin and Wicklow mountains. He began studies at the RUI medical school, Cecelia Street, in 1902. His last Dublin residence was at 7 Eccles Street, where he lived with two older female cousins (1908–10).
After casual acquaintance at Belvedere, Byrne became Joyce's closest university friend, a confidant to whom Joyce related his intellectual theories and personal intimacies, Byrne listening the while closely and silently, registering neither approval nor censure, but a rapt interest. Byrne was the basis of the character of Cranly in Joyce's novels (a nickname bestowed on him by Joyce early in their friendship), and of certain of the details of Leopold Bloom in Ulysses. The two fell out for a period (1902–3), when Joyce disclosed ribald details of his life in Paris to a mutual friend, Vincent Cosgrave, but not to Byrne; jealous of the confidence granted to another, Byrne snubbed Joyce on his return to Dublin. The friendship was restored by August 1904, when Joyce confided in Byrne the depth of his feelings for Nora Barnacle (qv); addressing Joyce's doubts on the matter, Byrne encouraged the couple's elopement to Europe if Joyce truly loved her. During Joyce's visit to Dublin in August 1909, he called on Byrne in great distress, having heard Cosgrave's allegation of Nora's infidelity during her and Joyce's courtship five years earlier. Byrne restored Joyce's trust in Nora, persuading him that Cosgrave's allegation was a malicious lie. Joyce memorialised the emotionally charged incident by appropriating Byrne's Eccles Street address for that of the fictional Bloom. A great supporter of Nora, Byrne described her as ‘a splendid, outstanding helpmate for James Joyce . . . this is what everyone ought to know now, and this is all they need to know’ (Maddox, 128). He visited Joyce and Nora in Paris in 1927 and 1933.
Byrne emigrated to America (April 1910), settling in New York city, where he worked in journalism, usually writing under the pen name ‘J. F. Renby’, an anagram of his own name. He hosted Francis Sheehy-Skeffington (qv), another university friend, at his home in Long Island City, Queens, during the latter's six months in America in 1915 evading re-arrest in Ireland under the cat-and-mouse act for making anti-recruitment speeches. Byrne spent most of 1916 in Ireland, observing and reporting on the political situation. Returning to America, he published a lengthy article, ‘The Irish grievance: the case for the anti-English party’, which included his eyewitness account of the Easter rising, in Century Magazine (January 1917). During the Irish civil war he organised an appeal signed by prominent Irish-Americans calling for an immediate cease-fire and negotiated settlement (October 1922). He became financial editor of the Daily News Record (1926–33), a Fairchild publication, for which he also wrote a daily financial column; he claimed to have forecast the stock market crash of 1929. Fascinated by cryptography, he invented a method and mechanical device for composing a purportedly unbreakable cipher, but failed in repeated efforts to interest the US government in the project. His autobiography, Silent years (1953), evinces the eccentricities of his ideas and personality, and records vignettes of his friendship with Joyce, including incidents and conversations adapted by Joyce to fictional purposes. He corresponded with Richard Ellmann (qv) during the latter's research for his biography of Joyce (1959), and warned Ellmann against too heavy a reliance on the testimony of Joyce's brother Stanislaus (qv), with whom Byrne's relations were always strained, and whom he described as ‘a bitter, frustrated, confused, and inaccurate man’ (Maddox, 520). Byrne's papers, including the Ellmann correspondence, are in the James Joyce collection in the Harry Ransom Humanities Research Center at the University of Texas at Austin. Byrne, who was married and had at least one daughter, died in 1960.