Student and Schoolmate reported in its February 1867 issue that the first installment of Ragged Dick "has created no little excitement among our numerous readers, as we supposed it would. Everybody is delighted." Scharnhorst observes that the Providence Evening Press, the Boston Transcript, the Christian Register, and the Monthly Religious Magazine waxed encomiastic with "simply charming", "excellent", and "spirited and inspiring". According to Scharnhorst, Booth Tarkington acknowledged the book as one of ten that made the "greatest impression on his life", and that in 1947 "the Grolier Club of New York selected it as one of the hundred most influential American books published before 1900."
Putnam's Magazine of July 7, 1868 wrote "Ragged Dick is a well-told story of street-life in New York, that will, we should judge, be well received by the boy-readers, for whom it is intended. The hero is a boot-black, who, by sharpness, industry, and honesty, makes his way in the world, and is, perhaps, somewhat more immaculate in character and manners that could naturally have been expected from his origin and training. We find in this, as in many books for boys, a certain monotony in the inculcation of the principle that honesty is the best policy, a proposition that, as far as mere temporal success is concerned, we believe to be only partially true. However, the book is very readable, and we should consider it a much more valuable addition to the Sunday-school library than the tales of Inebriates, and treatises on the nature of sin, that so often find place there."
Edwin P. Hoyt writes "Ragged Dick ... caught the American fancy ... [It] represented something virtually unknown to boys in the American countryside and totally unsung until [its publication]: the street waif who made his living in the jungles of brick and stone". Hoyt points out the Alger refined the many "stylistic tricks" he had been polishing for several years. The action displayed an authorial confidence, and the language captured the "coarse and ungrammatical" style of the metropolitan street boys. The book was a virtual guide to Manhattan in the year 1866, and "for that reason if for no other it approached the realm of literature". Hoyt points out that "[T]here had never been such a book ... one swindle after another is exposed to readers who had never heard of such things."
Scharnhorst indicates Alger's legacy resides not only in the several parodies and satires by William Dean Howells, Stephen Crane, F. Scott Fitzgerald, Nathaniel West, John Seelye, Glendon Swarthout, and William Gaddis, but also in the Horatio Alger Awards and in the many young readers who embraced his moral and humanitarian philosophy and were disinclined to embrace robber baron capitalism. Scharnhorst writes "It would seem that Alger was either over-rated as an economic and political propangandist or – more probably – his books were simply not designed thematically to spread the gospel of orthodox capitalism and convert the readership of The Masses.
In the HBO series Boardwalk Empire the book is given by Nucky Thompson to his nephew, saying that "he could learn a lot from it".