Baldwin's wife, Hilaria, came under fire Thursday from Daily Mail journalist George Clark, who reported that she tweeted upbeat posts during the funeral for James Gandolfini in a New York cathedral.
In a series of tweets after Clark's report, Baldwin went on a rant calling the journalist a "toxic Brit" and "toxic little queen."
The "30 Rock" star came under fire by critics who called his remarks homophobic.
He issued an apology letter to the media watchdog group GLAAD, People magazine reported Friday.
"My ill-advised attack on George Stark of the Daily Mail had absolutely nothing to do with issues of anyone's sexual orientation," he wrote. "My anger was directed at Mr. Stark for blatantly lying and disseminating libelous information about my wife and her conduct at our friend's funeral service. As someone who fights against homophobia, I apologize.
"I know women that act queeny, I know men that are straight that act queeny, and I know gay men that act queeny," Alec Baldwin told The Gothamist. "It doesn't have to be a definite sexual connotation, or a homophobic connotation. To me those are people who think the rules don't apply to them. This guy could blatantly lie, I mean blatantly lie about my wife on the Internet and there are just no rules that apply to him, but that's outrageous to me."