He is known for the cavalry regiment called 36th Jacob's Horse, and for founding the town of Jacobabad, in Sind province of British India (now Sindh in modern day Pakistan), where he planned and supervised the transformation of thousands of acres of desert into arable land over the course of twenty years.

[4] A number of the young cadets there who were his contemporaries, included such famous officers as Eldred Pottinger, Robert Cornelis Napier, Henry Marion Durand, Vincent Eyre and others.

He first saw active service in the summer of 1839 as a subaltern of artillery, the force led by Sir John Keane, sent to invade the Upper Sindh.

He was given command of the Sind Horse by Sir James Outram in 1841; in 1842 he was additionally placed in political charge of the whole of the Cutchee frontier.

Being an architect and an engineer himself, he designed and then executed the plans of laying a wide road network around the town that measured a good 600 miles (965 km).

[6] In 1856, due to Sir Bartle Frere's poor health, he taking leave in England, Jacob was pronounced Acting Commissioner in Sind.

Peace favourable to the British Government having been negotiated, Jacob was left in charge of conducting the evacuation of Bushire.

A month after the end of hostilities with the Persians, the Indian rebellion of 1857 had broken out; Jacob's Horse remained loyal throughout.

He was delayed in Bushire on the insistence of the British minister there, and Lord Elphinstone was unable to await his arrival; the command was given to Sir Hugh Rose instead.

[10] Controversy arose over a pamphlet Jacob published, "Letters to a Lady on the Progress of Being", which presented an early version of evolutionary theory.

This practice, according to Lambrick,[12] was discontinued on the orders of the Executive Engineer in the 1930s for the oil from the lamp left a messy stain on the grave.