She grew up in New York City and lived for years in St. Louis, Missouri, where her husband Jay Landesman operated the Crystal Palace nightclub.

While in New York, Deitsch met writer Jay Landesman, the publisher of the short-lived Neurotica magazine, whom she married on July 15, 1950.

After listening to musicians and audiences when sitting in the bar of the Crystal Palace, Fran Landesman was inspired to write song lyrics, from 1952 onwards.

One of her best-known is "Spring Can Really Hang You up the Most", her exploration of T. S. Eliot's "April is the cruelest month..." The Palace's pianist Tommy Wolf set her lyrics to music, and the song became a hit, leading to more Landesman–Wolf collaborations.

Molly Darling, a musical by Jay Landesman and Martin Quigley, was produced by the St. Louis MUNY Opera.

Fran Landesman also wrote the lyrics for a proposed musical version of A Walk on the Wild Side, adapted from the 1956 novel by Nelson Algren, known for his portrayal of down-and-outers.

Their "Small Day Tomorrow" has been recorded by many singers, and was the title of Dorough's 2007 CD, which featured 12 songs with Landesman lyrics.

[1] She wrote lyrics for a number of well-known musicians (with an emphasis on jazz) such as Pat Smythe, Georgie Fame, Tom Springfield, Richard Rodney Bennett and Dudley Moore.

[18] In 1996, Fran Landesman appeared on BBC Radio 4's Desert Island Discs and requested a supply of cannabis seeds as her luxury item.

Throughout 2010 and 2011, Landesman made bi-monthly appearances at RADA for Farrago poetry, and every six months hosted a lunchtime concert at the 606 Club in London.