Pearson was born at Tettenhall, then in Staffordshire, the eldest son of barrister John Pearson (1771-1841), a senior East India Company official who served as Advocate-General of Bengal from 1824 to 1840, and his wife Jane Elizabeth Matilda Hooke (1784-1833).

[1] Following his education at Eton, he was commissioned a cornet in the 11th Light Dragoons on 14 March 1825.

[1] That November, he fought at the Siege of Bharatpur under Lord Combermere and was a volunteer from the cavalry at the final assault on the fortress, for which he received a medal.

[1][2] Promoted lieutenant on 1 August 1826,[1] Pearson was ADC to the Earl Amherst during his visit to Maharaja Ranjit Singh, who presented him with a sword of honour for successfully riding an hitherto unmanageable horse.

[3] In December 1843, he fought under Sir Hugh Gough at the Battle of Maharajpur during the Gwalior campaign and was again decorated.