Arndell was born on 4 March 1753, in Kington, Herefordshire, England, to his mother Elizabeth and his father Anthony.
These surgeons, led by John White, acted as medical staff, who helped care for the convicts of the First Fleet.
He was made in charge of the Parramatta hospital soon after arriving at Port Jackson, and began to nurture the land there in 1791.
[2][3] Arndell settled into the Hawkesbury district, where he was a magistrate and is where he stayed for most of the rest of his life.
However, Lachlan Macquarie, the next governor, was impressed by Arndell's loyalty, and succeeded in convincing the British government to have his position reinstated.
He also had eight children to two other women before leaving England to migrate to Australia on the First Fleet: seven to Susanna Simon, two of whom survived to adulthood, and another to an Italian opera singer, Delicia Isabella Francesca Foscari.