Maher made the announcement Thursday during a performance of his "Crazy Stupid Politics" show in San Jose, Calif., aired on Yahoo!'s new live comedy Web channel.
"I would like to announce tonight a donation to the Obama super PAC, which has the very unfortunate tongue-twister name Priorities USA Action," Maher said.
"I know, it was named by Borat ... but tonight I would like to give that PAC 1 million dollars."
After the show, he tweeted to his 1 million Twitter followers, "Most important advice I ever got in show business, as true today as then: always bring ur wallet onstage."
In a second tweet, he said, "Thank u everybody who's hit me up after the show, and a great San Jose audience. Obama donation was a surprise to Yahoo too fyi!"