Jacobs was born in Australia, sixth surviving son of John Jacobs, a publican who had emigrated from London c.1837, and his wife Sarah, née Myers. Jacobs was educated at Sydney Grammar School and at the University of Sydney, where he won a scholarship for classics, mathematics and chemistry. He did not complete his studies in Sydney, but left for England at the age of 18 and entered St John's College, Cambridge. He graduated B.A. in 1876, and in 1877 studied at the University of Berlin. He was secretary of the Society of Hebrew Literature from 1878 to 1884, and in 1882 came into prominence as the writer of a series of articles in The Times on the persecution of Jews in Russia. This led to the formation of the mansion house fund and committee, of which Jacobs was secretary from 1882 to 1900.
In 1888 he prepared with Lucien Wolf Bibliotheca Anglo-Judaica: A Bibliographical Guide to Anglo-Jewish History, and in 1890 he edited English Fairy Tales, the first of his series of books of fairy tales published during the next 10 years. He wrote many literary articles for the Athenaeum, a collection of which, George Eliot, Matthew Arnold, Browning, Newman, Essays and Reviews from the Athenaeum was published in 1891. In the same year appeared his Studies in Jewish Statistics, in 1892, Tennyson and "In Memoriam", and in 1893 his important book on The Jews of Angevin England. In 1894 were published his Studies in Biblical archaeology, and An Inquiry into the Sources of the History of the Jews in Spain, in connection with which he was made a corresponding member of the Royal Academy of History of Madrid. His As Others Saw Him, a historical novel dealing with the life of Christ, was published anonymously in 1895, and in the following year his Jewish Ideals and other Essays came out. In this year he was invited to the United States of America to give a course of lectures on the "Philosophy of Jewish History". The Story of Geographical Discovery was published towards the end of 1898 and ran into several editions. He had been compiling and editing the Jewish Year Book since 1896, and was president of the Jewish Historical Society of England in 1898-9. In 1900 he accepted an invitation to become revising editor of the Jewish Encyclopaedia which was then being prepared at New York.
From 1899-1900 he edited the journal Folklore, and from 1890 to 1912 he edited five collections of fairy tales: English Fairy Tales, More English Fairy Tales, Celtic Fairy Tales, More Celtic Fairy Tales, and European Folk and Fairy Tales, which were published with distinguished illustrations by John Dickson Batten. He was inspired in this by the Brothers Grimm and the romantic nationalism common in folklorists of his age; he wished English children to have access to English fairy tales, whereas they were chiefly reading French and German tales; in his own words, "What Perrault began, the Grimms completed."
Although he collected many tales under the name of fairy tales, many of them are unusual sorts of tales. Binnorie and Tamlane are prose versions of ballads, The Old Woman and Her Pig is a nursery rhyme, Henny-Penny is a fable, and The Buried Moon has mythic overtones to an extent unusual in fairy tales. According to his own analysis of English Fairy Tales, "Of the eighty-seven tales contained in my two volumes, thirty-eight are Märchen proper, ten sagas or legends, nineteen drolls, four cumulative stories, six beast tales, and ten nonsense stories."
Jacobs settled permanently in the United States. He wrote many articles for the Jewish Encyclopaedia, and was generally responsible for the style of the whole publication. It was completed in 1906, and he then became registrar and professor of English at the Jewish Theological Seminary of America at New York. In 1908 he was appointed a member of the board of seven, which made a new English translation of the Bible for the Jewish Publication Society of America. In 1913 he resigned his positions at the seminary to become editor of the American Hebrew. He died on 30 January 1916. He married Georgina Horne and fathered two sons and a daughter. In 1920, Book I of his Jewish Contributions to Civilization, which was practically finished at the time of his death, was published at Philadelphia.
In addition to the books already mentioned, Jacobs edited The Fables of Aesop as First Printed by Caxton (1889), Painter's Palace of Pleasure (1890), Baltaser Gracian's Art of Worldly Wisdom (1892), Howell's Letters (1892), Barlaam and Josaphat (1896), The Thousand and One Nights (6 vols, 1896), and others. Jacobs was also a contributor to the Encyclopaedia Britannica, and James Hastings' Encyclopaedia of Religion and Ethics.
