The president of Ultimate Fighting Championship (UFC) will take the stage on Thursday night before Donald Trump – days after an assassination attempt – officially accepts the Republican presidential nomination.

Trump has embraced Dana White, one of his most outspoken supporters outside of politics, and the hugely popular combat sports franchise he manages, gracing several of its live events over the past year while grappling with court battles.

With an unfiltered and unorthodox style similar to Trump’s, the UFC boss will now act as frontman, introducing his long-time friend as the finale of the Republican National Convention.

Their friendship dates back to at least 2001.

Back then, Mr White – an Irish-American college dropout turned boxercise instructor – had gone from managing two mixed martial arts (MMA) champions to becoming UFC president.

MMA had been facing a downturn. After then-US Senator John McCain labelled it “human cockfighting” and led a campaign to ban the UFC, its events were consigned to small markets.

“This brand was so bad, venues didn’t even want us. Arenas didn’t want us,” Mr White said in 2022.

But after New Jersey legalised the sport in 2000, he continued, “Trump literally called us. He said ‘Come to my place, do the event here. We’ll have you at the Trump Taj Mahal’.”

The now-defunct casino and hotel in Atlantic City went on to host the UFC 31 and UFC 32 MMA events, with Trump showing up for the first fight and staying until the last on both occasions, according to Mr White.

Both events boosted the company’s profile and helped it secure larger venues for future events. Now the largest MMA promotion in the world, the UFC is currently valued at $12.3bn (£9.5bn).

And Mr White has stayed loyal to Trump through his evolution from business to politics.

Stumping for his friend at the RNC in 2016, he praised him in a short but fiery speech as “a hard worker” with “great business instincts”.

“I know fighters,” he said. “Donald Trump is a fighter, and I know he will fight for this country.”

Endorsing him again at the 2020 RNC, he championed Trump’s record in office and said it was “critically important to re-elect” him.

Brash and uncensored in both language and manner, the UFC chief has said he “does not give a [expletive]” about mixing business and politics.

No stranger to controversy himself, he admitted last year to slapping his wife after a drunken altercation at a New Year’s Eve party was caught on video. He has since apologised.

As Trump faced criminal, civil and other legal challenges in his post-presidency, he has been Mr White’s guest at multiple special events.

In the past year, Trump has attended at least four such events, often making fighter-style entrances with background music and an entourage.

His last scheduled appearance was scuttled this past Saturday by the attempt on his life at a Pennsylvania rally.

The UFC is replete with fighters who speak out in support of traditionally conservative values, including several self-described “pro-American patriots”.

Although it includes female fighters, the sport represents a hyper-masculinity that is arguably a good fit for the image generated by the Trump campaign.

Each time Trump has been received with thunderous ovations from clearly partisan crowds and taken VIP seats close to the octagon, or main fighting ring.

But he likely cannot replicate this growing love affair in other sports arenas, including those with Trump friendly audiences like Nascar and the PGA Tour, and the previously Trump-friendly WWE.

The failed assassination attempt on Trump has meanwhile reinforced his friend’s support for his re-election.

“Everybody wants to act like the tough guy. But when the [expletive] goes down, you find out who the tough guys are and who the tough guys are not,” Mr White told The Pat McAfee Show this week.

“This guy is the legitimate, ultimate, American badass of all time.”

Media reports indicate that Trump has rewritten Thursday’s nomination speech following Saturday’s shooting to make an explicit call for unity.

But if Mr White’s previous convention speeches are any indication, his introduction to the main event may not strike the same conciliatory tone.

The convention will also hear from controversial pro-wrestling legend Hulk Hogan.

And, as one Trump surrogate put it, the former president’s walk onto the stage is going to be like “Hogan at Wrestlemania”.