As part of her work for Lili, Deutsch wrote the lyric of the song Hi-Lili, Hi-Lo, which has been a popular bittersweet ballad for cabaret singers ever since. Branislau Kaper composed the music for it and the song was sung by Leslie Caron on the movie soundtrack.
In 1961, the Broadway version of the musical Carnival! was based on Lili and starred Anna Maria Alberghetti. Deutsch attempted to write the libretto, but was replaced by Michael Stewart. The show was nominated for two Tony awards.
Shortly after Deutsch's Barnard graduation, she was asked to write something to recite on a radio show to be aired just two days later in honor of the late actress Jane Cowl. Overnight, Deutsch wrote "The White Magnolia Tree." She then forgot about the poem. In 1957, she was commissioned by NBC-TV to provide a poem to be recited by Helen Hayes for the 50th anniversary celebration of General Motors. She got out her old poem, and Helen Hayes recited it with such tenderness that within a week thousands of people had requested a copy of the poem. General Motors provided it in booklet form. Helen Hayes herself made a 45 rpm of the poem and sent out hundreds of copies. It was released in Australia as His Master's Voice catalogue EA 52001.
In Australia, the Helen Hayes version was superseded when Gay Kayler (Gay Kahler) recorded her version of The White Magnolia Tree with a lush 32-piece orchestral backing. This became Gay's signature tune and remained in EMI and Reader's Digest catalogues (appearing on the Family Favourites box set) for more than 33 years.
Helen Deutsch died in New York City of natural causes.