Lily Delissa Joseph (née Leah Alice Solomon) was born into a Jewish family in Bermondsey, London, England on 24 June 1863; her brother was the artist Solomon J Solomon RA and her cousin was the portraitist Flora Lion (1876–1958). She trained at the Ridley School of Art and the Royal Academy of Art, becoming a portrait, landscape and interior painter and established a studio in Bedford Row, London, overlooking the Old Bailey. She first exhibited with the Society of Portrait Painters in 1891, as well as the New English Art Club (1888–1890s), the Women's International Art Club of which she was a member (1902–04, and postumously, 1963), the Society of Women Artists, and at the Royal Academy (1905–38), as well as in the Paris Salons - where she won a silver medal in 1929 and a gold in 1934 - and at the Glasgow Institute of the Fine Arts and Walker Gallery in Liverpool. In 1927 she showed two paintings (including a portrait of her brother) in the Exhibition of Jewish Art and Antiquities at the Whitechapel Art Gallery. She became known for her experimentation with a limited palette of white, cobalt, rose madder, orange madder and black.

Deeply involved in the women's suffrage movement, she was famously unable to attend her own Private View for her exhibition Some London and Country Interiors at the Baillie Gallery, London in 1912 after being detained at Holloway Gaol 'on a charge in connection with [the] Women's Suffrage Movement'. An advertisement to this effect was placed by her husband, the architect Delissa Joseph F.R.I.B.A. (1859–1927) , whom she had married in 1887, and who was very supportive of women's rights. An early cyclist, she was one of the first women to own and drive a car (motoring to Palestine in the 1920s), and also learnt to fly aeroplanes when in her fifties. A committed member of the Jewish community, she was also involved in many charitable ventures. In 1911 she met the young poet Isaac Rosenberg when painting at the National Gallery (she depicted its interior in at least twelve paintings including The Art Gallery, Ben Uri Collection). She employed Rosenberg briefly as a tutor to her children and her sister Mrs. Henrietta Lowy Solomon did the same, before introducing him to their wealthier friend Mrs Herbert Cohen, who sponsored Rosenberg's studies at the Slade School of Fine Art. Lily Delissa Joseph was also religiously observant and well-known for her musical voice in the communal singing at the Brook Green synagogue in Hammersmith (having also been active in its establishment).

In 1924 she had a joint exhibition with her husband Delissa Joseph, exhibiting 61 of her paintings (not for sale) alongside 64 of his drawings at the Suffolk Street Galleries. She also exhibited at Ben Uri Gallery including in Opening of the Ben Uri Jewish Art Gallery and an Exhibition of Works by Jewish Artists, Woburn House, London in 1934. Delissa Joseph built two of her brother Solomon's studios including one at Birchington in Kent, where, the Delissa Josephs also had a summer house, North Sea Lodge, and both brother and sister painted studies of their Birchington interiors. In 1937 her Roofs, High Holborn was purchased by the Chantrey Bequest for the Tate Gallery. Lily Delissa Joseph died in London, England on 24 July 1940. In 1946 the Ben Uri Art Society held a joint exhibition of paintings by Solomon J. Solomon and Lily Delissa Joseph at its London Gallery. She was also included posthumously in the group exhibition Jewish Artists of Great Britain, 1845-1945 at the Belgrave Gallery, London in 1978. Her work is represented in UK Collections including the Ben Uri Collection and Tate.