Son of Bhai Harbhaj and a grandson of Bhai Vasti Ram, occupied a position of honour at the court of Maharaja Ranjit Singh. A good scholar of Sanskrit and Persian, he was a trusted counsellor of the Maharaja, who consulted him on all important matters of State. He enjoyed the unique privilege of sitting on a chair in the presence of the Maharaja and his tent was fixed next to that of his master whenever he accompanied him on a military campaign. He sometimes acted as an interpreter at the Maharaja's meetings with his foreign visitors. He also acted as royal physician as he was adept in the use of indigenous herbs.

Respected as a religious head, Bhai Ram Singh placed the tilak on the forehead of Maharaja Kharak Singh when he ascended the throne of Lahore after the death of Maharaja Ranjit Singh. During the ascendancy of Prince Nau Nihal Singh, who had received pahul or Sikh initiatory rites at his hands, he rose in prominence and he was appointed to officiate as prime minister for a brief period in place of Dhian Singh who had proceeded on leave. Nau Nihal Singh bestowed upon him the famous Ram Bagh garden in Amritsar.

After the death of Maharaja Kharak Singh and Prince Nau Nihal Singh in November 1840, Ram Singh supported the claim of Rani Chand Kaur to the throne. Sher Singh who eventually won the crown was not favourably disposed towards him initially, but soon acknowledged his pre-eminence. According to the court historian, Sohan Lal Suri, the new Maharaja visited Bhai Ram Singh who gave him his blessing by offering eleven pieces of cloth as robes of honour, along with sweets. Sher Singh treated Bhai Ram Singh with respect and allowed him the privilege of a seat in the darbaras before. After the murder of Maharaja Sher Singh in September 1843, when Hira Singh Dogra became prime minister, Bhai Ram Singh again suffered a setback, but recovered his position as Hira Singh disappeared from the scene. Maharani Jind Kaur turned more to him than to anybody else for advice during the period she held the reins of power.

Bhai Ram Singh played a key role in the negotiations thatf ollowed the first Anglo-Sikh war (1845-46) and was one of the signatories to the treaties dated 9 and 11 March 1846 between the British government and the State of Lahore. He was a member of the Council of Regency set up to administer the State on behalf of the minor Maharaja Duleep Singh.
Bhai Ram Singh died at Lahore on 18 December 1846.