Shandling's spokesman said doctors believe he died of a heart attack. The Los Angeles Fire Department confirmed that it transported him to St. John's Medical Center after a report of a medical emergency at a home on Correa Way in Los Angeles at 10:40 a.m. Thursday.
His spokesman added that Shandling had no history of heart trouble. A coroner's official said Shandling died from natural causes and no autopsy is planned, but Lt. David Smith with the coroner's office said medical records will be used to determine Shandling's official cause of death.
Over a show-business career that lasted for more than 40 years, Shandling won acclaim as a sitcom writer, standup comedian, actor and producer.
But he earned the most critical praise of his career for "The Larry Sanders Show" on HBO, which aired from 1992 to 1998. He helped write and produce the show, and played the titular talk show host, in some ways a comic alter ego of his own neurotic persona. The show was nominated for 56 Emmys, winning three, and placed high on many critics' lists of the best TV shows of all time.
Shandling also appeared in numerous movies, including "Zoolander," "Captain America: The Winter Soldier" and "Iron Man 2." He hosted the Emmy and Grammy award shows multiple times.
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Comedians and actors who worked with Shandling or were influenced by him began offering praise for his work on Twitter.
Actress Kathy Griffin recalled seeing him recently: "Sunday, my longtime friend Garry Shandling was here, making every1 laugh. I loved him. I'll miss our talks the most."
Sunday, my longtime friend Garry Shandling was here, making every1 laugh. I loved him. I'll miss our talks the most. pic.twitter.com/Ud8AQXNBXN— Kathy Griffin (@kathygriffin) March 24, 2016
Late-night host Seth Myers tweeted: "Heartbreaking news about Garry Shandling. Just heartbreaking."
Comedian Albert Brooks wrote: "R.I.P. Garry Shandling. I am so saddened to hear this. Brilliantly funny and such a great guy. He will be so missed."
The Associated Press contributed to this report.