Eric Birling is first presented as the ne'er-do-well son of the wealthy and hardheaded businessman Arthur Birling, but later he proves his worth as an honest man.
Eric is an alcoholic, whose behavior has been dissolute and irresponsible, but his mother pretends that there is nothing wrong with her son. In the end, unlike his parents, Eric, along with his sister, demonstrates that he does possess a moral compass and a worthy conscience, by not excusing his guilt in the death of a poor young woman.
While the Birling family enjoys a celebratory dinner for their daughter Sheila and her fiance Gerald Croft, a police inspector arrives to question the family about a young woman named Eva Smith, who later calls herself Daisy Renton, who has committed suicide. The inspector shows each person separately a photograph, and he describes the poor girl's history.
At first, he talks to Mr. Birling and Gerald. However, as the drama develops, it is demonstrated all of the Birlings are involved in the tragic events that lead poor Eva to taking her life. The inspector also reveals that both Gerald and Eric have been romantically involved with Eva after her firing at the Birling factory and another job.
When Eva, who calls herself Mrs. Birling, appears before Mrs. Sybil Birling's charity group to appeal for financial help, the outraged Mrs. Birling prevents Eva from obtaining anything. She insists, ironically, that the father of the child must be held responsible. Eva tells her that this young man has given her some money, but she suspects that it has been stolen, so she cannot accept anything from him. (The young man, of course, is Eric and his impregnating Eva is why she has called herself Mrs. Birling.)
After all the inspector's revelations, Eric and his sister Sheila, who caused Eva's firing from a dress shop, admit their guilt. Further, Eric confesses to his father that he did, in fact, steal fifty dollars which he gave to Eva. Arthur Birling's first reaction is how to cover up the loss of the fifty dollars so no one will know. He tells his children that "a man has to mind his own business and look after himself and his own."
Further, Birling says there is reason to excuse his and his wife's behavior, but he is ashamed of Eric. On the other hand, Eric replies that he is ashamed of them, as well, as his father began her misfortunes and his mother directly caused her and his child to die. Nevertheless, in the end, the parents justify their actions because the inspector has performed a ruse and is not a real policeman. Only Eric and his sister accept their social responsibilities.