Pilar was born into an upper class family, the daughter of a Peruvian senator. She married and divorced professional big-game hunter Richard Weldy. She met John Wayne, 29 years her senior, in Lima, Peru, in 1953, while he was scouting locations for ”The Alamo." In 1953, Pilar came to Los Angeles to dub a film in English, when she ran into John Wayne for the second time. A year later on November 1, 1954, they married in Kona, Hawaii, the very same day Wayne's divorce became final. Pilar retired from her motion picture career to be a wife and mother to their three children: Aissa, Ethan and Marisa.
During the next ten years of their marriage, they traveled extensively, usually on location for John Wayne's many films. In 1965, they moved to Newport Beach, California. She and Wayne separated in 1976. She rented a studio inside the Fernleaf Courtyard, in Corona Del Mar, California. She would entertain her clients outdoors with coffee and finger sandwiches and found herself, one year later, with a full-time restaurant. John Wayne died of cancer on June 11, 1979.
In 1984 she married Stephen Stewart, a municipal court judge. They were later divorced.
In 1998, Pilar married Jesse Upchurch, a travel company executive. Pilar has created among other works of art, a collection of still nature and beautiful ladies, Belly Dancers called "Glamour Girls", as well as group images from the Hollywood world.