Mary Coyle Chase was born February 25,1907 in Denver, Colorado to Mary (McDonough) Coyle and Frank Bernard, a salesman. She graduated from high school at age 15 and studied at both University of Denver and University of Colorado before working for 14 years at the Rocky Mountain News. She received an honorary Doctorate of Literature from the University of Denver in 1947. She married a fellow reporter, Robert L. Chase, on June 7, 1928 and shortly thereafter was fired from her job as a result of a prank she played on her boss. She was reinstated but chose to leave to raise a family. She had three sons and lived in Denver at 532 W. Fourth Avenue, now an historic home. She died in 1981.

Inspiration for the play Harvey came from an encounter with an acquaintance during World War II. According to Chase, "she was a woman who had worked for years to send her only son through college. The day I looked at her, her boy had been dead about two months, killed in action in the Pacific. I asked myself a question: Could I ever possibly write anything that might make that woman laugh again?" One night Chase dreamed about a psychiatrist being chased by a giant white rabbit. Her four Irish uncles had told her stories of pookas, mischievous goblins or spectors held in Irish folklore to appear only to those who believe. The play took Chase two years to write, in the evenings when her children were in bed and her husband was at his job. She rewrote Harvey 50 times, trying it out on family, friends, and her cleaning lady before sending it to New York producer Brock Pemberton. He called her up a few nights later while she was reading a bedtime story to her boys to offer to produce the play.

Harvey opened on Broadway to rave reviews and played there for four and a half years, making it one of the five longest running Broadway plays. The success of her play did not go to Chase's head; the morning after the opening, she returned to her home in Denver, retrieved her children from friends, and began cleaning house and doing laundry. She had difficulty finishing her chores, however, because of the thousands of glowing phone calls and letters she received. Happily, her original question was answered when the woman whose son had died told her she had seen the play and had laughed. "And strangely," wrote Chase, "I got letters from many other parents from all over the country, people who had lost sons in the war. They all told me Harvey had brought them their first real laugh in months."