Marilyn Maxwell was a native of Clarinda, Iowa. She started her professional entertaining career as a radio singer while still a teenager before signing with Metro-Goldwyn-Mayer in 1942 as a contract player. Among the programs in which she appeared were Beat the Band and The Abbott and Costello Show. The head of MGM, Louis B. Mayer, insisted she change the “Marvel” part of her real name. She dropped her first name and kept the middle. Some of her film roles included Lost in a Harem (1944), Champion (1949), The Lemon Drop Kid (1951), and Rock-A-Bye Baby (1958). The song “Silver Bells” made its debut in The Lemon Drop Kid, sung by Maxwell and Hope. Maxwell appeared twice as a singer in the second season (1955–56) of NBC’s The Jimmy Durante Show. On May 16, 1957, she guest starred on NBC’s The Ford Show, Starring Tennessee Ernie Ford. In the 1961–62 television season, Maxwell played Grace Sherwood, owner of the diner on ABC’s 26-episode Bus Stop, a drama about travelers passing through the fictitious town of Sunrise, Colorado. She left the series after 13 episodes, saying, “There was nothing for me to do but pour a second cup of coffee and point the way to the men’s room.”

Maxwell married three times, each marriage ending in divorce. In September 1944, she married actor John Conte; they divorced in June 1946. Her second marriage, to restaurateur Anders McIntyre, lasted just over a year, from January 1, 1950, until they were divorced March 23, 1951. Maxwell’s six-year marriage to writer/producer Jerry Davis ended in 1960. Her only child, Matthew, was born to Maxwell and Davis in 1956. According to Arthur Marx’s Bob Hope biography The Secret Life of Bob Hope, Hope’s long-term affair with Maxwell was so open that the Hollywood community routinely referred to her as “Mrs. Bob Hope.” Maxwell also had a multi-year affair with Frank Sinatra, as detailed in Alex Gibney’s 2015 documentary on Sinatra for HBO, All or Nothing At All. In 1972, Maxwell’s 15-year-old son arrived home from school and found her dead at the age of fifty of an apparent heart attack, after she had been treated for hypertension and pulmonary disease. Bob Hope, Bing Crosby, Frank Sinatra, and Jack Benny were honorary pallbearers at her funeral.