He had been hospitalized in Chicago, Illinois, for more than a week with the lung infection.
Danica Smith, the comedian's publicist, had said Thursday that Mac's condition was "stable," The Associated Press reported.
"When I got the call this morning, it was just devastating news," said Chicago Sun-Times columnist Stella Foster. "Let's face it: Bernie Mac was one of a kind. He was the best of the best in terms of giving you a good laugh."
Smith previously said the pneumonia wasn't related to sarcoidosis, a lung disease Mac had, which had been in remission since 2005, according to AP.
Mac caused a stir in July with some jokes he made during a fundraiser for Democratic presidential candidate Barack Obama, AP reported.
Mac -- born Bernard Jeffrey McCollough -- starred in the Fox television series "The Bernie Mac Show." His film roles included the "Ocean's Eleven" series, "Friday," "Get on the Bus," "Transformers" and "Bad Santa."