Gujjar Singh Bhangi was one of the triumvirate who ruled over Lahore for thirty years before its occupation by Ranjit Singh, was son of a cultivator of modest means, Nattha Singh. Strong and well built, Gujjar Singh received the vows of the Khalsa at the hands of his maternal grandfather Gurbakhsh Singh Roranvala, who presented him with a horse and recruited him a member of his band. As Gurbakhsh singh was growing old, he made Gujjar Singh head of his band. Soon the band was united to the force of Hari Singh, head of the Bhangi Misl of chiefship. Gujjar Singh set out on a career of conquest and plunder. In 1765, he along with Lahina singh ,adopted son of Gurbakhsh Singh, and Sobha Singh, an associate of Jai Singh Kanhaiya , captured Lahore, from the Afghans. As Lahina Singh was senior in relationship, being his maternal uncle, Gujjar Singh allowed Lahina Singh to take possession of the city and the fort, himself occupying eastern part of the city, then a jungle. Gujjar Singh erected part of the city, then a jungle. Gujjar Singh erected a mud fortress and invited people to settle there. He sank wells to supply water. A mosque was built for muslims. The area, the site of present-day railway station of Lahore, still bears his name and is known as Qila Gujjar Singh.
Gujjar Singh next captured Eminabad, Wazirabad, Sodhra and about 150 villages in Gujranwala district. He then took Gujarat from Sultan Muqarrab Khan whom he defeated under the walls of the city in December 1765, capturing both the city and the adjoining country, and making Gujrat his headquarters. Next year, he overran Jammu, seized Islamgarh, Punchh, Dev Batala and extended his territory as far as the Bhimbar hills in the North and the Majha country in the south. During Ahmad Shah Durrani's eighth invasion, Gujjar Singh along with other Sikh Sardars offered him strong opposition. When in January 1767, the Durrani commander-in-chief reached Amritsar at the hed of 15,000 troops, the Sikh Sardars routed the Afghan horde. Soon afterwards Gujjar Singh laid siege to the famous fort of Rohtas, held by the Gakkhars, with the assistance of Charat Singh Sukkarchakia , who was on the most amicable terms with him and gave his daughter, Raj Kaur, in marriage to his son, Sahib Singh. Gujjar Singh subjugated the warlike tribes in the northwestern Punjab and occupied portions of Pothohar, Rawalpindi and Hasan Abdal.
Gujjar Singh died at Lahore in 1788.