The eldest son of the future president strode onto the stage at the 2016 Republican National Convention in a gray suit with his hair slicked back, awash in low expectations.

Donald Trump Jr.’s previous public appearances had been dutiful and less than dazzling — cameos alongside his father on “The Apprentice,” speeches for business audiences, a failed math quiz on Howard Stern’s radio show. Just a few months before his father entered the presidential race, Don Jr. was dabbling as a guest host of infomercials where he would interview executives marketing temporary office rentals and obscure construction techniques.

“What exactly is grip metal technology?” the real estate scion, stiff and unsmiling, asked one guest.

To prepare for his convention speech four years ago, Don Jr. practiced each day for a week. When he took the lectern, he started by praising his wonderful wife and mentioning their five children — and then identified himself as the son of “a great man.”

The speech was notable for its polish. The candidate himself would fulminate in his own speech about violence in the streets, but Don Jr. eloquently heralded his father’s common touch. His father “didn’t hide out behind some desk in an executive suite. . . . We didn’t learn from MBAs. We learned from people who had doctorates in common sense,” Don Jr. told a rapt crowd. He didn’t call Mexicans rapists. He didn’t hurl insults. As he went on, the speech developed its own cadence; soon, the packed convention hall was calling out “Trump!” after each of his rhythmic sentences.

The political world was dazzled. “Poised and focused,” wrote the New York Post’s John Podhoretz, calling it a speech Trump Sr. would never have been able to pull off. “I think I watched the speech of a future politician there,” said David Chalian, CNN’s political director. “In fact, a much better politician than his own father,” added Democratic strategist Maria Cardona, “and strikingly, much more knowledgeable in conservative orthodoxy than his own father as well. The pundit-class consensus was clear: Once Donald Trump’s crazy experiment in politics went down in flames that November, the son would be the one to watch out for.

Four years later, Don Jr., 42, who declined to comment for this story, has upended expectations again — or perhaps undermined them. Despite his father’s plan that he stay behind the scenes with his brother Eric and run the family business, Don Jr. has found a central role in the Trump universe, but not as a businessman or a poised and focused politician. Rather, he has become one of his father’s most aggressive and reliable defenders — a bombastic regular on Fox News, and a skilled meme-maker who relishes trolling the libs, flirting with some of the darker corners of his father’s base in the process. Don Jr. may well be the future of Trumpism after all — if Trumpism turns out not to be a political philosophy but a media-savvy culture-war incubator.

He is preparing for this year’s convention speech, scheduled for Monday night, the same way he did the last one, but he will come to the stage transformed. After a divorce, a special counsel investigation and countless skirmishes with his opponents, Don Jr. is battle-worn and grizzled — less constrained than he was four years ago, and far more confident.

After Trump's surprise win, CEOs flocked to meet with the president-elect's daughter Ivanka, in hopes that she would have her father's ear and perhaps help moderate his more extreme positions. Ivanka had always been viewed as her father's favorite, and now she and her husband, Jared Kushner, were anointed to go along to Washington. Her older brother, meanwhile, kept his head down. Don Jr. wasn't seen as a key conduit to his father's future administration. His main focus as a member of the transition team was to secure Ryan Zinke as interior secretary.

However, he had taken meetings during the 2016 campaign — including one in particular that would cause the entire administration problems.

“If it’s what you say I love it especially later in the summer,” he wrote in an email to a go-between offering to set up a meeting with a source promising dirt on Hillary Clinton, provided in cooperation with the Russian government.

The June meeting, with Russian lawyer Natalia Veselnitskaya, was a bust, but when it was first reported in the summer of 2017, it was the first evidence of any member of the Trump family showing openness to accepting help from Russian officials. It pulled Don Jr. into the center of what became the Mueller investigation — and led, indirectly, to his evolution as a key player in the conservative media world.

To hear his allies tell it, the negative attention that he received from the mainstream media about the Veselnitskaya meeting elevated him on the right as a symbol of media persecution. But Don Jr. had already started dabbling in controversy on his own.

After a September presidential debate, he tweeted an article from the conspiracy-theory-mongering site Infowars claiming that Hillary Clinton had worn an earpiece during the event. That same month, he shared on Instagram a Photoshopped image of him and other members of the Trump campaign in a heroic group pose (labeled “The Deplorables”) alongside a cartoon frog known as a white supremacist mascot. That same month, on Twitter, he compared Syrian refugees to a bowl of Skittles: “If . . . I told you only three would kill you, would you take a handful?” he posted. “That’s our Syrian refugee problem.” He promoted an article on the old, discredited conspiracy theory that the Clintons were involved in White House aide Vince Foster’s suicide.

The supportive attention from conservative media prompted him to lean into campaigning and fundraising for his father. And at any rate, by that point his ability to pursue new business for the Trump Organization was severely limited by conflicts of interest and damage to the brand from his father’s divisive policies. He started traveling with a camera-ready new girlfriend, former Fox News host Kimberly Guilfoyle, whom he started dating in 2018, and developed a smooth stump speech.

“Don’s become a force of nature on the political stump and has a genuine following because they see him out there fighting every day,” said Cliff Sims, a former White House communications official who remains close to Don Jr. “His dad sees him out there and it’s like a chip off the old block. He thinks he’s pretty good.”

Yet Don Jr.’s combative social media presence drew even more attention. “He lobs these meme bombs that are entirely provocative and are meant to be alienating to the left,” said Leslie Hahner, a professor of communications at Baylor University who studies the rhetoric of the alt-right. “He tends to wink to conspiracy theorists and white supremacists who amplify his father’s position.” And in turn, he repeats messages from all corners of social media with the imprimatur of the president’s son, drawing them “into the public conversation with a relevance they wouldn’t normally have,” Hahner adds.

Don Jr.’s allies say he’s just having fun and is sometimes oblivious about where the material originates. “It’s pretty simple, really,” Sims said. “The guy sees funny memes and puts them on Instagram.” August’s offerings have included memes implying that Joe Biden is cognitively impaired or supportive of urban riots and highlighting Bill Clinton’s relationship with the late financier and convicted sex offender Jeffrey Epstein (who also socialized with Trump Sr.).

Last month, Twitter ordered Don Jr. to delete a misleading tweet featuring a controversial group of doctors — proponents of the unproven drug hydroxychloroquine — claiming masks don’t thwart the spread of the coronavirus, contrary to established science and public health recommendations. The site suspended his account for 12 hours, prompting his press adviser, Andy Surabian, to claim on Twitter, “Big Tech is the biggest threat to free expression in America today & they’re continuing to engage in open election interference — full stop.”

Don Jr. has become a kingmaker in Trumpworld, using his social media network to elevate certain personalities in and around the administration. One such figure is Charlie Kirk, who became Don Jr.'s body man after meeting him at the 2016 convention. "If I don't like you, it's not going to work out," Kirk recalls Don Jr. telling him. But they hit it off, Kirk suggesting campus events they could do together in Midwestern swing states. Don Jr. went on to boost Kirk's Turning Point USA organization, dedicated to mobilizing conservative students, by speaking at well over 20 of their events — and more crucially, amplifying Kirk and Turning Point on social media.

“When Don Jr. retweets you, the biggest thing you get is [that] a lot of journalists follow Don, so whatever he retweets has a better chance of getting rewritten in other outlets,” Kirk said. “Whatever retweet pattern you were expecting, you can put an exponent on that when Don retweets you.”

Kirk also praised his mentor’s savvy when it comes to “the culture fights.” When the president last week rage-tweeted a demand for a boycott of Goodyear after a viral image of an employee training manual appeared to suggest the tire company had banned Make America Great Again hats but not Black Lives Matter insignia, Don Jr. fanned the flames with a more sharply articulated gripe: “You’re only censored if [you’re] a conservative,” he tweeted. “Now even corporate America will let you shill for a Marxist orginazation [sic] but not support the duly elected President of The United States.” (Goodyear maintained that the policy was a ban on all partisan political branding in the workplace.)

When Richard Grenell’s confirmation as U.S. ambassador to Germany was held up for months, Don Jr. vigorously championed his cause both on social media and through a network of media operatives and allies who helped keep the story alive in conservative outlets. After he was confirmed, Don Jr. promoted Grenell’s work, including his threats against German companies working on a Russian oil pipeline and his behind-the-scenes work to deport a former Nazi prison guard from the United States — all of them helping to generate the kinds of headlines his father loves. Grenell was later made acting director of national intelligence.

Now with his “MAGA Candidate of the Week,” Don Jr. highlights various congressional hopefuls, tweeting out fundraising links, filming promotional videos and recording robocalls.

“Don is a bigger asset to the future of the party than his father, regardless of the outcome of the election,” said Sam Nunberg, an early Trump adviser. And that party, as it has evolved over the past four years, isn’t likely to be offended by a few Pepe the Frog memes or ugly conspiracy theories. “The Republican Party in 2020 sure isn’t Mitt Romney’s party,” added a friend of Don Jr.’s, Rep. Lee Zeldin (R-N.Y.).

Before he decided to run for Senate, former attorney general Jeff Sessions held discussions about how to create an apparatus to carry on the ideals of the Trump movement — populism, nationalism, anti-immigration, protectionism. Though the talks never amounted to much, they did raise a natural question: What comes after Trump — or rather, who?

When his parents divorced, Don Jr. was 13 and didn’t speak to his father for a year. After college, he spent a year out West indulging his love of hunting and fishing, which he learned from his mother’s father during the summers he would spend with his grandparents in Czechoslovakia. These are pastimes in which his father has no interest — but which his allies say connect him to Trump’s base of supporters.

“If Don weren’t a Trump, he’d still be a guy in a MAGA hat, hunting on weekends and chanting ‘Build the Wall’ at rallies,” Sims said. “He’s a true believer, and that authenticity has helped fuel his rise as a political figure in his own right.”

Don Jr.’s bright future arguably depends on a certain discipline as he continues to juggle business responsibilities, campaigning, social media bomb-throwing, and multiple TV and radio appearances a week; he’s far more visible than Ivanka, whose profile has receded while his has grown.

Yet his momentum has been fueled by his embrace of a less staid and conservative persona than the world saw in 2016. At the end of 2018, he finalized his divorce from Vanessa, his wife of 13 years and mother of their five children. He’s now got a beard, an unburdened mien and an increasingly blustery, bleary manner in his cable-news appearances — far from the polite, buttoned-up executive seen on the national stage four years ago, in the days when Hillary Clinton, while grasping for something to praise about her opponent, cited his well-bred children.

The casual speculation that Don Jr. would someday run for president hasn’t completely subsided. But whatever his goal, he understands that his father had to become a cultural figure before he became a political one. So these days, as he focuses on trying to get his father reelected, he’s giving interviews to the likes of Barstool Sports, and launching his podcast, which shares the title “Triggered” with his first book. He avoids politicians for the most part, welcoming guests such as former football pros Herschel Walker and Burgess Owens and Ultimate Fighting Championship’s Tito Ortiz and Colby Covington.

In June, he made an exception for a filmed Father’s Day edition of the show, “with the most powerful father in the world,” Don Jr. crowed. His father responded with something between a smile and a grimace. The son’s first question, an attempt at jocular banter, was awkward: “Who is your favorite Trump child, and why is it Ivanka?”

It was his most popular episode ever.