Was born on 6 January 1896 in a land-owning family of tailors in the village of Dalelsinghvala, now in Bathinda district of the Punjab. His father's name was Kalu. His own name, Babu, was changed to Gurmukh Singh when he converted a Sikh and received the rites of initiation at the hands of Sant Atar Singh of Mastuana in 1913.

In 1914 he enlisted in the army where, because of his knowledge of Sikh scripture and tenet, he was entrusted with the duties of a regimental granthi or priest. He had himself released in 1919 from the army to make preaching his vocation. He took part in the Shahidi Samagam of 1921 to honour the memory of Nankana Sahib martyrs which launched him into Akali agitation for the reformation of Sikh shrines. He preached the reformed creed of the Singh Sabha and the Akali movement and was listened to with eagerness at divans, especially in the countryside. For a speech he delivered at Mansa Mandi, in the then Princely state of Patiala, he was arrested and spent an year and a half in jail.

In 1935-36, he entered Dera Baba Jassa Singh at Patiala, then the seat of Sant Nand Singh. The Dera remained Gurmukh Singh's headquarters for the next half-century. His sanctity and rustic humour and eloquence shed their influence on audiences in far-flung places, and he was constantly in demand at Sikh divans in India and abroad. In 1973, he was nominated a member of the Singh Sabha Centenary Committee. For his lifelong devotion to spreading the message of the Gurus, he was honoured at a special ceremony at the Akal Takht at Amritsar on 16 September 1975. Sant Gurmukh Singh was on one of his tours abroad when he suddenly died in New York on 19 June 1984.

Source: Encyclopaedia of Sikhism, Harbans Singh