Kylie Tennant was educated at the private girls' school, Brighton College, and attended the University of Sydney, but she withdrew in 1931 to live self-sufficiently with a female friend in the farming district of East Hills. Tennant retained a strong interest in the bush and sympathy for the plight of rural workers, experiencing first-hand the living-conditions of the poor during several long treks through rural New South Wales. One such trek took her to Coonabarabran where she visited a university friend, Lewis Rodd, who was stationed there as a teacher. They married in 1932 and in subsequent postings lived in Sydney, Muswellbrook and Laurieton, each providing settings and experiences for Tennant's fiction.
By 1935 Tennant had published a number of short stories in the Bulletin. On the urging of her father, she submitted the manuscript of her first novel, Tiburon, to the judges of the S. H. Prior Memorial Prize and won the award for 1935. Tiburon was serialised and published in book form by the Bulletin, establishing Tennant's reputation as a social-realist for her depiction of small-town life and the treatment of the unemployed. The integrity of such portrayals was supported by Tennant's thorough research that included travelling with itinerant workers and bee-keepers, living in Sydney's slums and remote Aboriginal communities, and even spending a week in gaol.
Tennant's fiction attracted attention in London and New York through the publishers Gollancz and Macmillan, respectively. Her study of nomadic workers in The Battlers (1941) drew comparisons with John Steinbeck's fiction and subsequent novels such as Ride on Stranger (1943), Time Enough Later (1943) and Lost Haven (1946) also attracted positive reviews. A number of these works were translated into several European languages. But when it became difficult to procure these novels in Australia during the 1940s, Tennant established the Sirius Publishing Company with her husband and father to print and distribute her works, an enterprise that lasted for several years.
Tennant's other works include travel literature, biography, award-winning children's books, plays and an autobiography, The Missing Heir (1986). Page restrictions and the possibility of libel forced Tennant to revise her proposed novel on prostitution, Tell Morning This, for Macmillan in 1953; it appeared as The Joyful Condemned later in that year and was published in its entirety by Angus and Robertson fourteen years later.
Tennant's various occupations included assistant publicity officer for the ABC, organiser for the Unemployed Workers' Union, reviewer for the Sydney Morning Herald and literary adviser and editor for Macmillan. Between 1957 and 1960 she delivered Commonwealth Literary Fund lectures at many Australian universities and was appointed a Member of the Advisory Board of the Commonwealth Literary Fund in 1961.
In 1980 Kylie Tennant was made AO. She died in 1988.