Mikhail Gorbachev was the last President of the Soviet Union, serving from 1990 until the USSR's dissolution in 1991. He was also the General Secretary of the Communist Party of the Soviet Union. Gorbachev is known for introducing significant reforms such as Glasnost (openness) and Perestroika (restructuring), which aimed to modernize the Soviet system. His efforts inadvertently contributed to the weakening of the Soviet state, culminating in the end of the Cold War and the eventual breakup of the USSR.