Bhagat Singh was born into a Sandhu Jatt family to Sardar Kishan Singh Sandhu and Vidyavati in a village in the Lyallpur district of Punjab.His ancestral village is the Khatkar Kalan village near Banga in Nawanshahr District of Punjab.The District has recently been renamed as Shaheed Bhagat Singh Nagar. Singh's given name of Bhagat means "devotee", and he was nicknamed "Bhaganwala" by his grandmother, meaning "The lucky one".He came from a patriotic Jatt Sikh family, some of whom had participated in movements supporting the independence of India and others who had served in Maharaja Ranjit Singh's army.His grandfather, Arjun Singh, was a follower of Swami Dayananda Saraswati's Hindu reformist movement, Arya Samaj,which would carry a heavy influence on Singh. His uncles, Ajit Singh and Swaran Singh, as well as his father were members of the Ghadar Party, led by Kartar Singh Sarabha Grewal and Har Dayal. Ajit Singh was forced to flee to Persia because of pending cases against him while Swaran Singh died in 1910 at his home after releasing from Borstle Jail, Lahore.
In his teenage years, Bhagat Singh started studying at the National College in Lahore, but ran away from home to escape early marriage, and became a member of the organisation Naujawan Bharat Sabha ("Youth Society of India"). In the Naujawan Bharat Sabha, Singh and his fellow revolutionaries grew popular amongst the youth. He also joined the Hindustan Republican Association through introduction by history teacher, Professor Vidyalankar, which had prominent leaders like Ram Prasad Bismil, Chandrashekhar Azad and Ashfaqulla Khan. It is believed that he went to Kanpur to attempt free Kakori train robbery prisoners from the jail, but returned to Lahore for unknown reasons.On the day of Dasara in October 1926, a bomb was blasted in Lahore, and Bhagat Singh was arrested for his alleged involvement in this Dasara Bomb Case in 29 May 1927, and was released on a bail of Rs.60,000 after about five weeks of his arrest.He wrote for and edited Urdu and Punjabi newspapers published from Amritsar. In September 1928, a meeting of various revolutionaries from across India was called at Delhi under the banner of the Kirti Kissan Party. Bhagat Singh was the secretary of the meet. His later revolutionary activities were carried out as a leader of this association.