According to three people familiar with Trump's thinking, he had been leaning towards Oz.
In Mar-a-Lago, Trump met with multiple people about the GOP primary, including Oz and David.
The battle for months over Trump's nod had been waged by the two men and their allies. With his loyal base and unparalleled popularity among Republican voters, Trump's decision to pick Oz could have a significant impact on the contest. Since some of Trump's candidates have faced challenges this year, Oz's success or failure at the polls will be a test of his own hold on the party.
Sean Parnell dropped out of the Senate race in Pennsylvania after being accused of abuse from his estranged wife.
The choice between Oz and McCormick was more difficult for the former president because Trumpworld is divided over the two front-running candidates. Some of Trump's allies have strong opinions on the primary in Pennsylvania, and he risks upsetting his friends if he chooses Oz.
Jim Worthington, a Pennsylvania Republican appointed by Trump to the President's Council on Sports, Fitness and Nutrition, told POLITICO earlier this week that he had spoken with Trump about Oz.
He said the president is fond of Oz.
A person aware of the meeting says that Oz and his wife, Lisa, had dinner with the former president and his wife at Mar-a-Lago.
While speaking to a crowd on the American Freedom Tour. Trump mentioned the celebrity television doctor while talking about the Pennsylvania Senate race.
Trump asked the crowd in Florida if anyone like Dr. Oz.
Other Trump allies are using their platforms to criticize Oz.
Steve Bannon, a former White House chief strategist to Trump, ripped into Oz on his show recently, saying that Oz is probably the most anti-MAGA guy.
Jack Posobiec, a far-right personality who was a guest on the show, said that the man wasn't around in 2020. But suddenly he found his way to Damascus conversion, and he has been hiding his conservative views for the entire time? Wow, that's news I think to everyone else in the movement.
In 2016 Oz had Trump on his show to conduct a health check-up, a decision that was criticized by some as a political stunt and favor to Trump.
In his statement endorsing Oz, Trump said, "He even said that I was in extraordinary health, which made me like him even more."
A person familiar with the meeting says that Trump and McCormick had a very productive meeting at Mar-a-Lago, where they talked about his finances, polling and ads. A source said that Rob Gleason, a former chair of the Pennsylvania Republican Party, met with Trump at Mar-a-Lago.
Trump's deputy national security adviser was Dina Powell. Former Trump White House staffers Hope and Stephen Miller, ex-Trump campaign adviser David Urban, and Trump White House lawyer Jim Shultz were all hired by the senator.
According to people familiar with their efforts, Fox News host Sean Hannity and casino mogul Steve Wynn both worked to get Trump to endorse Oz. Mrs. Trump is a supporter of Oz in the Senate race.
A person close to Trump said that the former president has been on TV in people's bedrooms and living.
Trump has used a variation of that phrase, emphasizing in conversations that Oz has been in women's bedrooms for years as they watched his daytime television program, something Trump believes would help him win suburban voters.
The person said that Oz had a certain level of trust associated with his TV career.
The support of Mrs. Trump for Oz is a testament to the belief that a celebrity like Oz has.
John Fredericks, a Trump friend who served as his Virginia campaign chair in 2016 and 2020, had the former president on his radio show. Fredericks, who met Oz at CPAC in February and just endorsed him, opened the interview with a question about whether Oz is a Trump candidate.
He's a good man, too, and I had a good experience on Oz's television show for a health check-up during the election.
Trump said a decision would be made on that one.
In an interview, Fredericks wouldn't say if he had private conversations with Trump.
Fredericks said before Trump's announcement that his decision would be based on what was best for the country. Bush's Department of Treasury was headed by McCormick.
It's understandable that Trump views Oz's name ID and celebrity status as positive attributes since he launched his 2016 presidential campaign, according to a former Trump campaign aide.
Dave is proud to be aligned with his America First agenda and President Trump's continued popularity across Pennsylvania is obvious.
Trump's endorsement is a risk with the primary contest still unresolved.
While Oz started the primary with a clear lead and officially announced his candidacy a month and a half ahead of McCormick, several surveys show the dynamics of the race have changed.
A Fox News poll in March had Oz at 15 percent, but another recent poll found a dead heat.
Jim McLaughlin, the pollster for the campaign, said that the former business executive and Oz were the top two vote getters. He said Oz has an unfavorable rating.
Republican primary voters in Pennsylvania have seen through him. He said that they understand that Mehmet Oz is not a Pennsylvania conservative.
Oz's campaign released an internal poll that showed him at 24.8% and McCormick at 21.6.
Other candidates in the Republican primary include a former ambassador under Trump, a conservative commentator, and a real estate developer.