In a memorial statement upon the death of Kingsley in 1995, Robert Anderson wrote:

Sidney was part of that extraordinary group of playwrights who came into being in the 1930s and 1940s, which heralded the arrival of the new American theatre and the new American drama.

Kingsley is generally remembered as a noteworthy but minor American playwright whose works addressed serious social problems in popular, dramatically well-crafted Broadway plays. He is praised for his dramatic craftsmanship in writing emotionally engaging yet serious melodramas that also carry a moral message.

Kingsley's plays have been applauded for their treatment of issues pertaining to American democracy and their expression of hope that justice and democracy will prevail over corruption and tyranny. In her introduction to Sidney Kingsley: Five Award Winning Plays, Nena Couch observed, "Kingsley has used his naturalistic writing style to present major American social problems on the stage...