Saroo was born as Sheru Munshi Khan in Khandwa's Ganesh Tilai neighbourhood (Madhya Pradesh). As a young boy, his father left his mother, catapulting the family into poverty. His mother worked at construction sites to support herself and her three children. She couldn't afford to send them to school, so when Saroo was 5, he along with his older brothers Guddu and Kallu, began begging at the railway station.

One fateful evening, Saroo accompanied Guddu to ride the train from Khandwa to the city of Burhanpur, which was 70 kilometers down south. By the time the train reached Burhanpur, Saroo was so exhausted that he collapsed on one of the platform seats. Guddu promised him that he would return shortly, but he never did; leaving Saroo to fend for himself.

Saroo noticed a train parked at the station and climbed onto it thinking his brother was on it. He fell asleep and when he woke up, the train was crossing a territory unfamiliar to him. Saroo couldn't get down from the train as he was unable to open the door whenever the train stopped at small stations.

He eventually ended up at Kolkata's Howrah Railway Station, almost 1500 kilometers away from home! After scavenging for food in the streets, sleeping underneath the station's seats and being chased by two "wrong people", Saroo met a teenager who took him to a government center for abandoned children.