On 9 April 1839, Senhouse commissioned . He was sent from England to fill the office of second-in-command of British naval forces in China, where he served in the First Anglo-Chinese War. Commodore Gordon Bremer, commander-in-chief of British forces, entrusted the attack on Anunghoy Island to Senhouse in the capture of the Bogue forts on 26 February 1841. After the "Blenheim" fired broadsides from starboard at the island's fort, Senhouse landed with about 300 marines and seamen to clear the few remaining defenders. On 31 March, Bremer sailed to Calcutta in the steamer "Queen" to confer with Lord Auckland about the state of affairs and request reinforcements, leaving Senhouse in command of the naval forces.