Joginder Jaswant Singh was born on 17 September 1945 at Samma Satta in the Punjab, the first child of Lieutenant Colonel Jaswant Singh Marwah (b. 1921) and his wife Jaspal Kaur (1923–2006). Sama Satta was then a town in the princely state of Bahawalpur State, now part of Pakistan. His family originated from the town of Daultala, now also in Pakistan, Rawalpindi District. He is a third-generation soldier; his paternal grandfather Sepoy (Private) Atma Singh Marwah (1896-1968) enlisted in the 1/67 Punjab Regiment of the British Indian Army as a drummer in 1914, and fought at the Siege of Kut in the Mesopotamian Campaign during the First World War. Wounded in his right elbow and arm early on, he was evacuated and sent to recuperate in the south of France, after which he was discharged from the army in 1918. Joginder's father, Jaswant, is a veteran of the Second World War who passed out from the Indian Military Academy in April 1943 and was commissioned into the Royal Indian Army Service Corps. In 1943, he was posted to the Reserve Supply Depot at Karachi, and married his wife Jaspal Kaur in December 1944. In February 1945, he was posted to Sama Satta and given command of a petroleum sub-depot; Joginder was born that September. After independence and Partition in August 1947, the family migrated to Patiala in India. In 1948, Jaswant transferred to the Indian Army Corps of Electrical and Mechanical Engineers as a Captain.