The actor and former bodybuilder said the Russian politician “belongs to history” and that he was “unbelievably lucky” to have called him a friend.
Gorbachev, who led the Communist Party of the Soviet Union from 1985 until 1991, died on Tuesday aged 91.
Sharing a picture of the pair together on social media, Schwarzenegger wrote: “There’s an old saying, ‘Never meet your heroes.’ I think that’s some of the worst advice I’ve ever heard.
“Mikhail Gorbachev was one of my heroes, and it was an honour and a joy to meet him. I was unbelievably lucky to call him a friend.
“All of us can learn from his fantastic life.”
Under Gorbachev’s leadership the Soviet Union underwent a period of Glasnost, during which Russian citizens were permitted more freedom of expression.
In his post, Schwarzenegger continued: “Imagine rising to the very top of any organisation, and then having the wisdom AND the courage to look around and say, ‘This doesn’t work for the people, someone has to fix it. If not me, who? If not now, when?’
“Mikhail Gorbachev did exactly that in the old Soviet Union. He will be remembered for all time as a hero who dismantled the communist system despite what it meant for his own power.
“He belongs to history now, and I know he’s overjoyed to be reunited with his dear Raisa, once again living one of the greatest love stories of all time.
“When you see a chance to make an impact, to leave a better world for the next generation, I hope you’ll think about Gorbachev and ask yourself, ‘If not me, who? If not now, when?’ I know I will.”