During the Jamaican slave uprising, Hamilton Brown was a lieutenant colonel in the St Ann Western Division of the island militia. Serving under Colonel James Hilton, he was posted on 1 January 1832 to Rio Bueno, at the border between the parishes of Trelawny and St Ann. In Hilton's view, an uprising of enslaved people in the area was poised to commence and he wrote that a ‘regular place of insurrection was organized in this neighbourhood’. Hilton therefore sent a company of 100 mounted troops under Brown to Harmony Hall and Lancaster estates and reported to his commander-in-chief, Willoughby Cotton, that Brown's men ‘speedily reduced the Insurgents to reason’. The next day Brown, who like other slaveholders believed that enslaved people had been compelled to rebel because of ‘the bad advice of the Methodists & Baptists Parsons’, rode with his men to properties in the district to ensure enslaved people there were at work and to challenge any signs of disaffection. A letter to the St Jago de la Vega Gazette alluded to the terror tactics that were used by such militia companies. The author wrote that ‘Colonel Hilton, immediately on his arrival, caused to be made known in the neighbourhood, and particularly on those properties the slaves of which were disaffected, that he would annihilate the first party that dare to perform the smallest act of rebellion’.

Brown worked hard to repress the uprising and was proud of what he did. His ride around the estates in the vicinity of Rio Bueno covered over thirty miles, and his men rode at full charge between properties. Of the eleven estates his detachment went to, he wrote that ‘with the exception of Manchester I found the Negroes all at work’. At Manchester he claimed that the ‘negro houses … had 14 of the Ringleaders’. He arrested these men and took them back to Hilton, who sent them on to the town of Falmouth for trial. As the remaining insurgents retreated, Brown was involved in the hunt for fugitives in St James.