“I’m going to run for president,” Walsh said Sunday in an interview on ABC News’s “This Week,” charging that the president is “incompetent,” “a bigot” and “a narcissist.”
Former Massachusetts governor Bill Weld also has declared that he is running against Trump in the Republican primary, but he has struggled to gain traction.
Asked about Walsh’s entry into the race, Trump campaign spokesman Tim Murtaugh replied, “Whatever.”
Weld, meanwhile, welcomed Walsh’s arrival, saying he was “thrilled” by the news.
“I think that’s terrific,” he said on NBC News’s “Meet the Press.” “And it’s going to be a more robust conversation. Who knows? The networks might even cover Republican primary debates.”
In Sunday’s interview, Walsh staked his run on harsh criticism of the president and questioned Trump’s support among Republicans, despite polls showing that the president is popular with the overwhelming majority of GOP voters.
According to a Monmouth University poll released last week, 84 percent of Republicans approve of Trump’s job performance. His highest recent approval mark among fellow Republicans was 88 percent in a Fox News poll of registered voters earlier this month.
“He’s nuts. He’s erratic. He’s cruel. He stokes bigotry. He’s incompetent. He doesn’t know what he’s doing, George, he’s a narcissist,” Walsh told host George Stephanopoulos.
Walsh also released an announcement video in which he called on Americans to have “the courage to finally say publicly what we all know privately: We’re tired.”
“My name is Joe Walsh. I’m a former Republican congressman. I’m a conservative. I’m running because Donald Trump is not who we are. In fact, he’s the worst of who we are,” Walsh says in the video.
In the “This Week” interview, Walsh apologized for his past criticism of former president Barack Obama during his time in office, saying he and other tea party Republicans helped create a partisan political environment that facilitated Trump’s election.
“I got personal and I got hateful. I said some ugly things about President Obama that I regret … that helped create Trump, and I feel responsible for that,” he said.
But Walsh has also made inflammatory comments in more recent years, and Stephanopoulos raised some of those remarks in the interview, describing them as “textbook racism and sexism.”
“Obama is a Muslim,” Walsh tweeted in December 2016, adding, “Happy New Year!”
Stephanopoulos noted Sunday that Walsh “called President Obama a Muslim, an enemy, a traitor. And you often spoke out on racial themes.”
Walsh, who has said he voted for Trump in 2016, responded by claiming that the president’s rise had caused him to reconsider his past remarks.
“Well, again, the beauty of what President Trump has done is, George, he’s made me reflect on some of the things I have said in the past,” he said. “I had strong policy disagreements with Barack Obama, and too often I let those policy disagreements get personal.”
Stephanopoulos pressed him: “Did you really believe he’s a Muslim?”
“God no,” Walsh replied. “And I have apologized for that.”
Walsh also faced a child-support dispute with his ex-wife that ended in a settlement in 2012.
Others who are mulling Republican primary challenges against Trump include Mark Sanford, a former South Carolina governor and congressman, and former Ohio governor John Kasich.
Jeff Flake, a former senator from Arizona and a Trump antagonist, also has said he has taken a flurry of recruitment calls from GOP donors rattled by signs of an economic slowdown and hungry for an alternative to Trump.
Robert Costa and Scott Clement contributed to this report.