Lala Lajpat Rai, popularly known as 'Punjab Kesari', was born on 28 January 1865 at village Dhundhike in Jagraon tehsil of the Ludhiana district, Punjab, in a Hindu Aggarwal (Bania) family. His mother, Gulab Devi, came from a Sikh family. Lajpat Rai's family was far from affluent; his grandfather, Lala Rala Ram, was a shopkeeper, and his father, Lala Radha Kishan, an Urdu teacher in a Government school.

Lajpat Rai had three brothers, Dhanpat Rai, Ranpat Rai and Dalpat Rai. He was married to Radha Devi (1877) who came from an Aggarwal family of Hissar. He had two sons, Amrit Rai, Pyare Lal, and one daughter, Parvati.

Lajpat Rai studied first at the village school and then at the Mission High Schools at Ludhiana and Ambala. He passed the Matriculation examination at fifteen and joined the College at Lahore (1880) for his Intermediate and Law. He completed his final Law examination in 1886. He taught for some time at the D.AV. College, Lahore, but soon took up law as his profession, and practised it first at Hissar and later at Lahore.

Lajpat Rai's interest in Politics was aroused by his father who in his early life was a great admirer of Sir Syed Ahmed Khan but whom he condemned later for his anti-Congress tirade in an open letter which appeared in the Koh-i-Noor, an Urdu journal (1888). Lajpat Rai too had shared his father's admiration for Sir Syed Ahmed Khan but from 1888 began to criticise in his writings the anti-Congress activities of Sir Syed. Lajpat Rai's father was well-versed in Urdu and Persian languages, had great respect for Islam, fasted and prayed like a Muslim, but did not embrace Islam largely dut to his wife's attachment to the Hindu and Sikh faiths.

The Arya Samaj movement, a vital force in the Punjab in the late nineteenth and early twentieth century, had a tremendous appeal for Lajpat Rai (he had met Swami Dayanand at fourteen), who came under its influence from his student days. It was Lajpat Rai's attachment to the Arya Samaj which led his father also to veer round to Hinduism. The Arya Samaj work brought Lajpat Rai into close touch with Lala Chura Mani and Pandit Lakhpat Rai at Hissar, and Lala Sain Dass, Mahatma Hans Raj and Pandit Guru Datt at Lahore.