Renowned man of letters and custodian of Sri Darbar Sahib at Amritsar in Sikh times, came of a devout family of Chiniot, in present-day Jhang district of Pakistan. His grandfather, Bhai Ram Singh had spent his life preaching Sikhism in those parts. His father, Bhai Surat Singh, made home in Amritsar to which place he had migrated in 1750. Surat Singh was a scholar of Persian and Punjabi and enjoyed high reputation as an exponent of the Gurus' teaching. For his lucid discourses on the Sikh sacred texts, he was popularly known as giani, i.e. a man of spiritual insight and knowledge. After the occupation of the Punjab by Sikh misls, Bhai Surat Singh was appointed manager of the Darbar Sahib at Amritsar and of the jagirs earmarked for its maintenance.

For himself, he was.granted a landed estate near Jalandhar where he built a small fortress. Sant Singh was born in this house in 1768. He trained in Sikh religious lore at Amritsar under the care of his father. Soon he and his younger brother, Gurdas Singh, were assigned to reciting the Guru Granth Sahib in the Harimandar. Later, Sant Singh studied Braj and Sanskrit under Pandit Nihal Singh of Thoha, now in RawalPindi district of Pakistan. When MaharajaRaniit Singh occupied the Jalandhar Doab in 1806-07, he allowed Bhai Sant Singh to retain the family estate and appointed him to succeed his father in the superintendence of repair and decoration work at Sri Darbar Sahib at Amritsar. Sant Singh also began to attend the court at Lahore. In 1821, he accompanied Ranjit Singh on an expedition to Mankera in the Sind Sagar Doab in Western Punjab. Saddened by the untimely death of his younger brother, Bhai Gurdas Singh, Sant Singh forsook court life and retired to Amritsar to devote himself to reading and expounding the Scripture at Sri Darbar Sahib, his son, Gurmukh Singh, replacing him at the court. In Amritsar, Sant Singh was also entrusted by Ranjit Singh with the task of having art and filigree work carried out in the interior of the Harimandar and having the upper portion of the exterior covered with gold-leaf. An inscription at the main entrance of the inner sanctuary commemorates the services of the Maharaja "whom the Guru by his own favour had assigned to the seva" and of Giani Sant Singh who supervised execution. In addition to his administrative responsibilities, Sant Singh continued his scholarly study of and discourse on Scripture.

A very fortunate circumstance was his acceptance of Bhai Santokh Singh as a pupil who was given lodging in his own house, Burj Gianian. Bhai Santokh Singh produced in Braj verse that inimitable and immortal work on the lives of the Gurus and Banda Singh Bahadur, Sri GurPratap Suraj Granth. Among Bhai Sant Singh's own extant works is the famous Suras Pradipaka, a translation in prose of Tulsidasa's Ramayana, which was published in the Devanagari script in 1897. Sri Guru Charitra Prabhakar, published at Chashma-i-Nur Press, Amritsar, in 1877, contains short biographical accounts of the Gurus. Another work by him was on pahul or the rites of initiation among the Sikhs.

Bhai Sant Singh died at Amritsar in 1832. His work at Sri Darbar Sahib was taken over by his son, Bhai Gurmukh Singh.