He was the son of Maha Singh, a small faction leader at the head of a misl, one of the numerous entities comprising the region at that time. During childhood, he suffered from smallpox, which resulted in the loss of one eye. He succeeded his father at the age of twelve.
During the summer of 1799, Ranjit Singh conquered the misl of Lahore, the economic capital of the region, with the ensuing expansion leading to his being crowned Maharajah of Punjab at the age of twenty. He then launched an attack on the Afghans, acquiring many territories where Islam was the predominant religion.
Although some of their conquests were violent, the Sikh Empire proved to be very progressive and open-minded for those times. All religions were freely allowed there, and the very rigid Hindu system of social castes did not apply in the Sikh religion, in which all men were considered equal. With the annexation of Kashmir to the north and Sindh to the south, Muslims represented more than 70% of the subjects in the Sikh Empire.
Wanting to have his memory live on in the Sikh religion, Ranjit Singh ordered the sacred temple of Harmandir Sahib to be adorned. He had marble installed there, and had the exterior covered entirely in gold leaf.
From then on, the western world referred to the sacred center of the Sikh religion and culture as the "Golden Temple".
Even today, Ranjit Singh is venerated by Sikhs across the entire world as one of the great heroes of their culture. A bronze statue approximately seven meters high (22 feet) representing Maharajah Ranjit Singh was unveiled in the vicinity of the Indian Parliament in August 2003.