He was born into a family of nine children, of whom the five sons who grew to adulthood all joined the service of the East India Company.
He was educated at East India Company College 1818–20, winning a prize in Persian.
On furlough 1840–3, Udny was sub-treasurer to the general treasury Bengal 1843, and retired on the annuity fund 1851.
[1] Returning to the United Kingdom, Udny became a barrister of Lincoln's Inn 6 June 1855.
[6][7] Their daughter Louisa Tempe Udny, born in Calcutta in 1837, was an activist for female education and in feminist politics.