Priestley's play, at its heart, is an indictment of the class system in Edwardian England, and as such the generational disparities between characters are some of the primary movers in this purpose; the older generation are a relic of an outdated model of class and pro-capitalist sentiment, whereas the younger generation represent a hopeful future congruent with 1946 more than 1912.

Starting with the older generation, we can see that the patriarch, Mr Birling, and his wife (his "social superior"), represent a generation that is wedded to the 'old ways', and contemptuous of the "younger generation who know it all and [...] can't take a joke". The language choice is deliberate and stirring in Mr Birling's comment, here; to him, the family's involvement in the downfall of a young working-class woman amounts to a "joke" if she has not died. Indeed, both he and his wife remain resolute and firm that they did "nothing to be ashamed of", the adjective "ashamed" being a crucial feature of their indifference; they do occasionally resist culpability until pressed, but they are consistent in their refusal to 'feel bad' about their actions -- a huge distinction. As a "hard-headed man of business" and a "rather cold woman", Mr and Mrs Birling represent the unfeeling harshness of capitalism that Priestley sought to undermine with his vocal support for left-wing politics in the build-up to 1945's ousting of the Tory party.

In stark contrast, despite their roots, we find the Birling children, Sheila and Eric, whose initially smug and carefree attitudes are shaken permanently by the Inspector's intervention, and who are "frightened [by] the way [their parents] talk". Sheila, who starts the play as a giggly and naive girl, and who "wishe[s]" she hadn't been told about Eva's death when she had been "so happy tonight" but who quickly becomes the voice of reason and the most hopeful figure by the play's conclusion. Eric, too, though much less forgivable for his actions in the eyes of a modern audience, is cast as a sympathetic figure who learns his lesson and condemns his father for his heartlessness ("you're not the sort of father a chap could go to if he was in trouble"). The Inspector's suggestion that "the younger ones [are] more impressionable" seems to be a direct ventriloquism of Priestley making a claim about the progressive nature of the young voters in the '40s who spent the last decade seeing the need for social reform, not least in the Beveridge Report that highlighted the plight of the poor.

Finally, there is Gerald, a character who, by virtue of both his age and his lifestyle, does not belong in either category. Whilst the Birling parents and children are fairly one-dimensional archetypes, Gerald is not, and is as such perhaps the focus of Priestley's attention. Gerald is older than his fiancée but not in his fifties like Birling, and occupies a strange position: "too masculine to be a dandy but very much the well-bred man about town". By "too masculine", Priestley clearly means that he tries to fashion himself as a "man of business" like his esteemed father, of Crofts Ltd., but by "man about town", he is clearly indicating that this man is a socialite. In the eyes of Priestley, a character like this is worse than the Birling parents: not a new-money capitalist who at least worked his way up, nor an old-money philanthropist who used wealth for the support of (select) others in society -- but instead a self-serving quasi-dandy who should have no authority on anything but who makes the bold claim at the end that "everything's all right now" in spite of his actions.

The play's treatment of the different generations in society is deftly handled and provides social commentary on the world of 1912 that has been subsumed by a hopeful future in post-war 1946.