painter and illustrator, was born on 14 August 1893, second daughter of Colonel Charles Dennys, who was stationed in India, and Mary Tulloch, from Scotland. She studied at the Exeter and London Schools of Art. She was a VAD during World War I and nursed wounded soldiers from Britain and the Commonwealth in Exeter. On 2 January 1919 she married Thomas Cann Evans, who came from Budleigh Salterton, Devonshire but had been working in Australia as a doctor at the outbreak of war and joined up as a major in the Australian Army Medical Corps. After the war they lived at Kyogle, New South Wales, where Evans worked as a doctor, until 1921 when they returned to England. Their daughter was born in England in 1922.
Dennys’ distinctive, witty style made her drawings immediately popular in post-war Sydney’s sophisticated artistic circles. She had work accepted for the Bulletin soon after her arrival; two originals of cartoons published 6 and 20 November 1919 are in the Mitchell Library. The latter is an elegant drawing of two working-class women gossiping over the fence with a corny gag clearly added by the editorial staff: When the Sleeper Woke . '“Oh, Mrs. Clubb, I 'ad sich a scare in the night! I was awakened by 'earing a loud crashing noise. I struck a match, and the first thing I saw was a man’s legs stickin’ out from under the bed.”/ “Oh, dear, it was the burglar!”/ “No, my dear, it was me 'usband. 'E 'ad 'eard the noise, too!”’
Art in Australia reproduced drawings by her in July 1919. The September 1920 issue of Home included her strip illustration, 'The Quaint Story of Pamela’, who lost seven maids in six weeks and took over the household duties – successfully. A stylish cover of maid and mistress adorned Home in March 1921. She had drawings in the August issue and in September 1921 another comic multi-incident sketch, 'Twelve Hours in the Life of a Richmond River Belle’, illustrated the exhausting day of a young woman on a dairy farm who nevertheless remains fresh in the evening while her dancing partner (a strapping male) is wilting and complaining. T.C.C. Evans was the Kyogle doctor; Joyce Dennys’s understanding of a rural woman’s life was gained first-hand.
She kept in touch with the metropolis and exhibited designs and genre scenes with the NSW Society of Artists. A watercolour and pencil sketch of a naughty girl and cross servant, I Don’t Like Cook , was purchased from the 1919 annual exhibition by the National Art Gallery of NSW, although it did not normally collect illustrations primarily intended for children. The drawing reappeared in 1920 as plate 45 in the Society of Artists Pictures , a special number of Art in Australia , along with another 'Water-colour Drawing’ by Dennys, The Child Next Door (plate 58). In July 1920 she had a solo exhibition of her watercolours 'of a whimsical fancy, and a close observation of child-life and character’ at the Salon of Fine Art in Sydney, which, one reviewer stated, showed at times 'almost a masculine strength’ in the drawings but luckily 'not insistent enough to take away the charm of femininity’.
Although not much interested in children’s book illustrations either, Home reviewed the new edition of Amy Mack’s Bushland Stories in December 1921 and praised the 'entirely new illustrations in colour and black and white by Joyce Dennys… so admirably suited to their subjects, so beautiful in their delicacy of tone and drawings’. Her illustration of a boy unwillingly being accompanied by a fairy was reproduced. The other forty-six drawings are equally unsentimental and appealing, despite a certain gender stereotyping typical of the period: the boy chases a frog, the girl sympathetically watches a flower fairy 'weeping like an ordinary child’. Dennys obviously delighted in the 'ordinary’ aspects of a subject and was able to express them in an original, lively style with which her subjects readily identified.
After returning to England in 1921 Dennys mainly worked for the theatre, writing plays for adults, children’s pantomimes and a West End musical set in Australia called Kookaburra (late 1950s). She illustrated her own novels and stories written both for adults and children: 39 titles written and/or illustrated by Dennys are in the British Library catalogue. Sketches produced during the Second World War were later published in two volumes: Henrietta’s War, News from the Home Front 1939-1942 and Henrietta Sees it Through, More News from the Home Front 1942-1945 (London, c.1985 and 1986). She died in London aged 97.