Bayh was born in the Garfield County, Oklahoma town of Lahoma, and was the daughter of Bernett E. (née Monson) and Delbert Murphy Hern. Her ancestry included Norwegian, German, and English. She married Birch Bayh in 1952 and moved to Indiana. When Birch Bayh decided to run first for the Indiana House of Representatives in 1954 and then for the US Senate in 1962 she began her career as a political wife.
Bayh suffered from a variety of health problems as the result of a car accident shortly after her marriage. Despite recurring back problems and double vision, Bayh remained deeply involved in the Washington political and social scene. She and her husband also survived a plane crash in 1964 that killed two people and critically injured Senator Ted Kennedy.
The Bayhs were close friends with Senator Kennedy and his wife Joan Kennedy, as well as President John F. Kennedy and Jacqueline Kennedy. As an Oklahoman, Bayh also formed warm and close relationships with President Lyndon B. Johnson and Lady Bird Johnson.
Bayh had a keen interest in current events and public affairs and was a skilled campaigner and public speaker. In 1967, President Johnson recognized her abilities and asked her to become the vice-chairman of the Democratic National Committee—a job she turned down with great reluctance at the request of her husband who was launching his own Senate re-election campaign.
Personal tragedy also marred her family life. Her mother died early from heart failure, and her father became a violent alcoholic later in life, eventually murdering his second wife and then taking his own life.
In 1971, Bayh faced another personal crisis with a diagnosis of breast cancer. She underwent a mastectomy followed by radiation and chemotherapy treatments. In order to support his wife, Birch Bayh announced that he would not be a candidate for president in 1972.
After her recovery, Bayh became a spokesperson for the American Cancer Society. She was also a television "Bicentennial Reporter" every Sunday through July 4, 1976.
In 1978, more than six years after her cancer operation and treatment, the cancer recurred. Despite aggressive treatment, she lost her battle and died on April 24, 1979 at the age of forty-six, in Bethesda, Maryland.
- Smith, J.Y. (25 April 1979). "Marvella Bayh Faced Challenges of Life With Courage". Washington Post. Retrieved 25 February 2016.
- Bayh, Marvella and Kotz, Mary Lynn. Marvella: A Personal Journey. New York City: Harcourt, Brace Jovanovich, Inc., 1979.