Jacqueline Mars was born on October 10, 1939. She attended and graduated from the boarding school Miss Hall's School in Pittsfield, Massachusetts. She graduated from Bryn Mawr College in 1961 with a degree in anthropology.
Mars married David H. Badger in 1961. They had three children: Alexandra Badger born 1966/1967 (age 51–52), Stephen M. Badger born c.1969 (age 48–49), and Christa Badger born c.1975 (age 42–43). She divorced Badger in 1984. She married Hank Vogel in 1986; they divorced in 1994.
On October 4, 2013, Mars was involved in a car accident on U.S. Route 50 in Aldie, near her home in The Plains in Northern Virginia. Her vehicle crossed the highway center line and struck a Chrysler minivan carrying six passengers. One person died at the scene, while another was pregnant and subsequently miscarried. Mars was charged with reckless driving, and told a witness after the accident that she had fallen asleep at the wheel. Mars subsequently pleaded guilty to the misdemeanor charge of reckless driving, with tests having revealed no drugs, alcohol or medications in her system that could have caused a blackout.
Mars is a heiress to Mars, Inc. shares. As a member of the Mars family, Mars' shares of Mars, Incorporated and other assets were estimated by Forbes magazine in January 2018 to be worth $27.8 billion, making her the Forbes described Mars as the 17th richest American, and #22 on its list of "The World's Billionaires".