Caroline Leakey was born at Exeter, England, in 1827, the daughter of portrait painter, James Leakey. Her education was limited by life-long ill health, but her life was dominated by a strong Christian faith. In 1847 she travelled to Hobart Town, Van Dieman's Land, to join her sister and brother-in-law, the Reverend James Medland. However, she contracted fever a year later, leaving her an invalid for the next five years. (Shirley Walker in Wild and Wilful Women : Caroline Leakey and the Broad Arrow has suggested that Leakey's ill-health may have taken the form of anorexia and that she probably had an addiction to laudanum.)
During her time of illness in Hobart Town Leakey began to write poetry. Some of this poetry was published after her return to England in 1853 as Lyra Australis, or Attempts to Sing in a Strange Land. After acting as head of her deceased sister's school, she returned to Exeter to care for her aged father in 1855.
In 1857 Leakey began writing the novel for which she is remembered: The Broad Arrow; Being Passages from the History of Maida Gwynnham, a Lifer (1859). It is recognised as one of the earliest novels with a convict as its primary character, anticipating Marcus Clarke's His Natural Life (1870-74). The novel has been criticised for its sentimentality, melodrama and homiletic. But it remains an important contribution to the convict literature of Australia for its examination of the effect of transportation on convicts by someone with first-hand knowledge. In the following years Leakey wrote tracts and poems for Girls' Own Paper and later worked at the Exeter Home for fallen women.
Caroline Leakey died at Exeter in 1881.