When she was a little girl, Mary Chase's three Irish uncles, Pete, Tim, and Jamie, amused her with stories from Celtic mythology of pookas and banshees. Chase was born in 1907 in Denver, Colorado, which is probably the model for the "western town" where Harvey takes place. She attended college in Denver and married Robert Lament Chase, a newspaper reporter, in 1928. Chase herself worked as a newspaper reporter at that time, first for the Rocky Mountain News and then as a freelance correspondent for United Press and International News Service. She gained reputation for being one of the best "picture stealers" in the Denver news business, visiting households of victims or criminals and walking away with stolen photographs of the involved person from the family's collection.

Chase's first play was Me Third, which was produced in 1936 for the Federal Theater Project, a government agency aimed at keeping...