During the beginning of the Sepoy Mutiny in 1857, also known as the Great Revolt of 1857, Sir Robert Montgomery became the Lieutenant Governor of Lahore in Punjab, British India, in May 1857. He instantaneously disarmed the native garrison that forbade them from taking any action in the Indian rebellion. Montgomery was awarded with a knighthood for this action. He was later appointed as the Chief Commissioner of Oudh on 3 April 1858. He served the position till 15 February 1859.
Sir Robert Montgomery GCSI, KCB, LLD was later elected as the second Lieutinent Governor of Punjab. He served in office from 25 February 1859 to 10 January 1865. Montgomery was preceded by Sir John Lawrence and succeeded by Sir Donald McLeod. He served as the Lieutenant Governor of Punjab in British India, up to an advanced age. He was knighted with the Knight Grand Commander of the Most Exalted Order of the Star of India and the Knight Commander (KCB) or Dame Commander (DCB) of the Most Honourable Order of the Bath, (formerly known as The Most Honourable Military Order of the Bath).
Sir Robert Montgomery GCSI, KCB, LLD was married in British India and also had a family in the nation. Henry, his second son, was the father of Field Marshal Montgomery. Montgomery died in the year 1887 in British dominated India. After his death, his son Henry inherited the family estate in Ireland.