The authoritarian leader of the Soviet Union during the Great Purge was Joseph Stalin. From the late 1920s to the early 1930s, he implemented this campaign to eliminate dissent within the Communist Party and consolidate his power. The Great Purge involved widespread political repression, mass arrests, show trials, and executions of perceived enemies, including party members, military leaders, and ordinary citizens. This brutal crackdown aimed to instill fear, enforce loyalty within the party, and suppress any opposition to Stalin's regime. Ultimately, it resulted in the deaths of hundreds of thousands and left a lasting impact on Soviet society and governance.