"It was touch and go for a while," said the singer, who appeared to have lost weight during his time in a Vienna hospital.
"They spent three weeks keeping me alive basically. I don't want to take you through all of it because some of it I want to protect my family from and I'm sure I'll get it all written down, but it was by far the worst month of my life," he said.
The former Wham! frontman said his staff downplayed the severity of his illness to avoid alarming his fans.
He implied that he had been in a coma when he talked about having "woken up" 10 days ago. He also revealed he had undergone a tracheotomy while in the hospital.
Michael, 48, was rushed to AKH Hospital in Vienna late last month after canceling a performance in the Austrian capital. He was released from the hospital Thursday.
The singer behind hits such as "Faith" and "Father Figure" said the experience would make him more spiritual and appreciative of his life.
"I have an amazing, amazing life and if I wasn't spiritual enough before the last four five weeks then I certainly am now," he said.
The Associated Press contributed to this report.