At the film's conclusion, after the credits, we see Kate and Sean standing in their garden waving good-bye. Maureen O'Hara turns to John Wayne and whispers something in his ear, evoking a priceless reaction from Wayne. What was said was known only to O'Hara, Wayne and director John Ford. In exchange for saying this unscripted bit of text, O'Hara insisted that the exact line never be disclosed by any involved parties. In her memoirs she says that she refused to say the line at first as she "couldn't possibly say that to Duke", but Ford insisted, claiming he needed a genuine shock reaction from Wayne. The line remains a mystery to this day.
In the scene where John Wayne discovers Maureen O'Hara in his cottage, the wind whipped her hair so ferociously around her face she kept squinting. John Ford screamed at her in the strongest language to open her eyes. "What would a bald-headed son of a bitch know about hair lashing across his eyeballs," she shot back.
In 1986, the wife of a young New York police officer, who was shot and paralyzed on the job, saw fit to tell reporters this was her husband's favorite movie and that he adored Maureen O'Hara. After reading the report, O'Hara flew to New York and went to the officer's bedside to offer comfort and boost his morale. She became actively involved with the couple during his long recovery and physical therapy, attended their baby's christening and marched in a parade on his behalf.
Charles B. Fitzsimons (Hugh Forbes) and James O'Hara (Father Paul) were the real-life younger brothers of Maureen O'Hara (Mary Kate Danaher).