The Age of Innocence was a softer and more gentle work than The House of Mirth, which Wharton had published in 1905, and which was set in the time of her childhood. In her autobiography, Wharton wrote of The Age of Innocence that it had allowed her to find "a momentary escape in going back to my childish memories of a long-vanished America... it was growing more and more evident that the world I had grown up in and been formed by had been destroyed in 1914." Scholars and readers alike agree that The Age of Innocence is fundamentally a story which struggles to reconcile the old with the new.
Wharton was raised in the old world of rigid and proper New York society which features in the story. She had spent her middle years, including the whole of World War I, in Europe, where the devastation of a new kind of mechanized warfare was felt most deeply. As explained by Millicent Bell in the Cambridge companion to Wharton, "The Age of Innocence was composed and first read in the aftermath of Roosevelt's death and in the immediate wake of World War I. We frame the ending remembering the multiple losses… not only the loss of Roosevelt but the destruction of the prewar world and all that Wharton valued in it."
The Age of Innocence centers on an upper-class couple's impending marriage, and the introduction of the bride's cousin, plagued by scandal, whose presence threatens their happiness. Though the novel questions the assumptions and morals of 1870s New York society, it never develops into an outright condemnation of the institution. The novel is noted for Wharton's attention to detail and its accurate portrayal of how the 19th-century East Coast American upper class lived, as well as for the social tragedy of its plot. Wharton was 58 years old at publication; she had lived in that world and had seen it change dramatically by the end of World War I.
The title is an ironic comment on the polished outward manners of New York society when compared to its inward machinations. It is believed to have been drawn from the popular painting A Little Girl by Sir Joshua Reynolds that later became known as The Age of Innocence and was widely reproduced as the commercial face of childhood in the later half of the 18th century. The title, while ironic, was not as caustic as the title of the story featured in The House of Mirth, which Wharton had published in 1905.