Jochi was the eldest son of Genghis Khan and the founder of the line that ruled the Golden Horde. His birth in around 1182 occurred shortly after his mother, Börte, was rescued from abduction by the Merkit tribe. This timing created persistent doubts about his paternity, leading to lifelong rivalry with his brothers, particularly Chagatai. Despite these disputes, Genghis Khan officially recognized Jochi as his firstborn son, ensuring his place in the imperial succession and military command.
Jochi participated actively in his father's campaigns, playing a crucial role in the conquest of Siberia and the northern forest tribes. During the major invasion of the Khwarazmian Empire (1219-1221), he commanded the right flank of the Mongol army, capturing cities along the Syr Darya river. In the siege of Urgench, the capital of Khwarazm, tensions erupted between Jochi and his brother Chagatai over how to treat the city, which Jochi hoped to preserve as part of his future domain. Genghis Khan eventually intervened, placing their younger brother Ögedei in command of the siege.
After the Khwarazmian campaign, Jochi retired to his assigned territories in the western steppes. Under the system of imperial division, he was granted the westernmost lands of the empire—stretching as far as the hoof of a Mongol horse could reach—which later became known as the Ulus of Jochi. He died in 1227, just months before his father's death. Jochi's legacy lived on through his sons, particularly Batu Khan, who conquered Eastern Europe and established the Golden Horde, and Orda Khan, who founded the White Horde. In Mongolian tradition, Jochi is remembered as a capable leader who laid the foundation for the expansion of the western empire.