Daughter of the French artist, Jules Lessore RI and brother of Frederick Lessore, she studied at the Slade from 1904 to 1909. She began exhibiting with Frank Rutter's Allied Artists' Association in 1912 and in the following year showed with the Camden Town artists in their Brighton exhibition. A founder member of the London Group, she was first married to the Group's president Bernard Adeney. She exhibited over a hundred works with the London Group and served on the Group's hanging committee from 1917 to 1919. Her first solo exhibition was staged at the Eldar Gallery in 1918 and her choice of subjects from domestic interiors to music halls showed the influence of Sickert. Writing about her work in 1916 Sickert noted, 'Miss Lessore has the gift of stimulating perpetual curiosity, and of leaving it unsatisfied. I am always wishing that she would tell us a little more here and there. Perhaps if she did the spell would be broken.' Following a divorce from her first husband, she married Sickert in 1926 and from then on her output was much reduced. She was included in the 1974 Michael Parkin Gallery exhibition, The Sickert Women and the Sickert Girls.