She was born in London in 1962 to a diplomatic correspondent father and a writer mother of Chinese descent (mother, Esther Cheo Ying, wrote a memoir Black Country Girl in Red China, about her time serving as a Major in Mao Zedong's Red Army). Following a troubled childhood, she joined the publishing industry, through which she met the writer Heathcote Williams, with whom she had her first son, Charlie. Following their split, Samson met Pink Floyd singer and guitarist David Gilmour. They married in 1994 during Pink Floyd's Division Bell tour. They have three children named Joe, Gabriel, and Romany Gilmour and currently live in West Sussex. She continues to collaborate with Gilmour on several of his songs, primarily in a lyrical capacity. She has also written short stories for BBC Radio 4 and has had a collection published Lying in Bed (Virago 1999) and a novel, Out of the Picture (Virago 2000), as well as contributing pieces and stories to many other books and publications including Gas and Air (Bloomsbury 2003), Girls Night In (Harper Collins 2000), A Day In The Life (Black Swan 2003), and The Just When Stories (Beautiful Books 2010).

Samson is credited as a co-writer on six of The Division Bell's 11 tracks, and, with vocalist Clare Torry (co-writer of Great Gig in the Sky), she is one of only two female co-writers of any Pink Floyd songs.

She wrote lyrics for Gilmour's 2006 album, On An Island, and made a guest appearance on piano and vocals.

Virago will publish Polly Samson's new collection of stories, Perfect Lives, in November 2010.