Born Marian Maud Runnells (she later changed the spelling of Marian to Marion) in Natchez, Mississippi, she began her career in Atlanta working clubs, and then in Chicago where singer Peggy Lee heard her on an audition tape and suggested she should be signed up by Capitol Records, releasing three albums for them in the early and mid-1960s. During this early part of her career, she became Marian Montgomery, having previously gone by the nickname of Pepe.
In 1965, she came to England to play a season with John Dankworth and met and married English pianist and musical director Laurie Holloway, thus beginning a long and productive association in which they both became very well known to British jazz, cabaret and television audiences. She numbered amongst her admirers Nat King Cole, Frank Sinatra and British chat show host Michael Parkinson, on whose show she became resident singer in the 1970s. She also famously collaborated with composer and conductor Richard Rodney Bennett for a series of concerts and albums in the 1980s and early 1990s.
Her recording of the song "Maybe The Morning" (contained on her 1972 album Marion in the Morning), was used by Radio Luxembourg each evening to close the station in the late 1960s and early 1970s and again as the final song to be heard on the station when it closed in 1992. She is judged to have been amongst the very best of modern jazz singers and to have possessed a unique musical style along with an equally unique way of expressing the sentiments of her material. Montgomery never categorized herself purely as a jazz singer, rather simply as “a singer”. This is reflected in the huge variety of styles she sang, although she acknowledged her influences as being jazz based. Her final studio recording was That Lady from Natchez, released in 1999. She continued to perform until just before her death, including a sell-out three week season at London’s Pizza on the Park in April 2002.