19 July 2017. My phone rings. White House operator: “Please hold for the president.”

I do. Of course.

President Trump: “What are you doing tomorrow for lunch?”

Me: “Having lunch with you.”

Working for Trump wasn’t just a huge mistake. It gave me the opportunity to make a lot of other huge mistakes. I got famous for them, and in the fallout, my whole life looked like it would fall apart.

The previous January, Trump had offered me a job: director of the Office of Public Liaison, the White House unit that interacts with interest groups. Reince Priebus, Trump’s chief of staff, blocked that appointment. Steve Bannon, the chief strategist, was also against my working in the White House. I was a traditional moderate Republican type with connections to Trump’s daughter Ivanka and her husband, Jared Kushner. The Kushner group made up one silo in the administration. Priebus made another silo: the Republican National Committee. Bannon was Maga far right. All silos were mutually hostile: Priebus and Bannon were leaking on each other constantly. But they allied in not wanting me anywhere near Trump.

I called Trump to tell him my job had been blocked and I didn’t want to fight with Priebus. I also told him he was going to have problems with Bannon and Priebus, and when he did, he could call me and I’d help him fix it. I said it cavalierly, egocentrically. “Call me if you ever need help with those bad guys.” I didn’t know if he’d ever call.

But in July the phone rings, and the White House operator is asking me to hold for the president.

On the phone, Trump tells me to avoid the press outside the White House by going to the East Wing entrance. He’ll have an escort waiting to take me to the study off the Oval Office. When I get to the study, we sit down and he says, “Yeah, you were right about Priebus and Bannon; I need to get rid of them. You’re a New Yorker. You and I always got along. I want to bring you in.”

He calls the White House operations guy. “What office is open here in the West Wing?”

The guy reminds him he’d never replaced Mike Dubke, who had resigned as communications director. Trump hangs up and says, “You’re going to be comms director.”

My first reaction was: I can’t be comms director. I have no experience. How the hell am I going to do that job?

Trump’s attitude was more like: it’s just like the campaign – we’ll figure it out together. So I left the White House that day in July, scheduled to return the next morning for a meeting in the Oval Office to announce my new position.

I checked into Trump’s DC hotel. Meanwhile, Priebus and Bannon started freaking out. The operations guy must have called them and tipped them off, and they were desperate to make sure I didn’t get the job.

The next morning, I was having a cup of coffee at the hotel when my phone rang: Priebus and Bannon. They offered me ambassadorships – Paris, or I could pick one – but told me I couldn’t come to the White House. To capture the tone of White House interactions in general, and my style in that particular moment, I have to put it this way: I basically told them to go fuck themselves. They asked me to meet with them before the Oval Office announcement. So I met with them in the chief of staff’s office and called them dicks who were leaking on each other and hurting the president.

In other words, things were not going well. Already.

I’m a front stabber. That’s not the way to be if you want to get things done in Washington. Priebus, from Kenosha, Wisconsin, tries to come across as Richie Cunningham from Happy Days, all “golly gee”. I called him Kenosha Nostra: basically a mobster and a backstabber. He’d been dropping bombs on me with the press, the kind of back-channel rumour-leaking that in Washington they call ratfucking.

Later that morning, in a meeting with Trump, Priebus and staff secretary Rob Porter, the president turned to Porter and said, “I want Anthony directly reporting to me.”

That was a bombshell for everybody, including me. It meant I’d be bypassing Priebus as chief of staff and undermining Sean Spicer, the press secretary. I’d been planning to fire Spicer anyway, but still, I was looking nervously at Trump. I’d rather have reported to the chief of staff. I was already getting the idea that there was a lot going on.

I might not last even 90 days in this job, I thought.

Little did I know.

Trump looked at Priebus. Then he actually said these words to me: “I don’t want his filth tainting you.”

That was a moment. Priebus kept up his “howdy doody” thing, trying to pretend he wasn’t pissed at Trump, but he couldn’t hide how pissed he was at me. That same morning, Spicer announced his resignation. One less firing I’d have to do – but now the whole place was nervous. A New Yorker was coming in to work with a New Yorker. And this New Yorker was obviously here to clean house.

I called a big meeting in the Roosevelt Room. I explained the situation very bluntly, based on my observations. Trump had come in looking, basically, to find out what presidents do all day, and the people around him were giving him conflicting ideas, so the administration was now siloed among people who hated each other.

The RNC was against Trump. The Maga people were fighting with each other, three fiefdoms at war: the Kushner fiefdom, the Priebus fiefdom and the Bannon fiefdom, all dropping bombs and ratfucking each other. And pissing off Trump. That’s what I was there to change.

Next came my press conference. Probably 30 or 40 million people watched it, and you can still watch it today, on YouTube. If you do, you’ll see it goes very well.

But it doesn’t go well. Not at all. I’m articulate. I handle the Spicer resignation and say nice things about Priebus. I’m answering the press’s questions. I’m reasonably telegenic. I’m saying good things about Trump.

Trump doesn’t like any of that. There’s one spotlight. It’s a one-man show. The better I do, the worse I’m doing, but I don’t get that. I think I’m at least doing great at communicating. Then, after the press conference, as I’m going back upstairs, I get a call from one of the operatives on Capitol Hill.

He says, “You can’t talk like that from the White House, telling the truth to the American people. Everyone here is upset about that. You’re getting too much attention. You’re talking in complete sentences. Trump’s gonna fucking fire you. Be careful.” I said to myself, I’m never doing another press conference. But that wasn’t going to work. Because I couldn’t read the situation. Meaning I couldn’t read Trump.

He was inexperienced in the job of the presidency and that made him uptight. One of the many big mistakes I made was how I talked to him in the White House. I kept talking to him the way I’d talked during the campaign. It’s pretty well known that I tend to use profanity when I’m relaxed, but that wasn’t the problem. It was that I was still being blunt.

During the campaign, when I thought Trump was doing something stupid, I’d say, “This is fucking stupid.” And he would look at me and say, “Well, why is it stupid?” And then, if he agreed with me, he wouldn’t do it; and if he didn’t agree, he would keep doing it. He told Jared Kushner I reminded him of his dad, Fred Trump. I said whatever was on my mind; I was classic New York; I made money on my own, didn’t inherit it from my father. So he sought out my opinions.

When I got to the White House, I kept talking to him like that.

Right away, I now see, it irritated the hell out of him. He was president of the United States. He expected to be flattered with total obsequiousness by everybody he talked to. I didn’t see it then.

So I didn’t give another press conference, but over the following weekend, I was asked to do TV interviews, and I should have told them no, but I didn’t. The attention got me in more trouble with Trump.

And it wasn’t just Trump. I was alienating everybody else. I mean everybody.

On the Monday, I flew with Trump to West Virginia, where he was going to address the boy scouts’ National Jamboree. Another mistake. Just flying with him causes jealousy, which leads to more bomb-dropping with the press and further attempts by Bannon and Priebus to unravel me. At the Jamboree, Trump speaks for 29 minutes and says almost nothing that’s not completely insane, so I have to do what I can to clean that up.

Meanwhile, my wife, Deidre, was giving birth. I wasn’t there. Where was I? I was in West Virginia, cleaning up after the president.

I said my judgment was impaired. Now you know. Deidre had told me not to get involved with Trump, and she was so fed up with my decision-making that during her pregnancy she’d filed for divorce – no half measures like a separation, but outright divorce. I didn’t want that. But if I was trying to make things right, nobody would have known.

I just hurtled forward. On the job.

Tuesday, I was back on Air Force One – again, a mistake just in itself – to Youngstown, Ohio, while scrambling to cope with the boy scouts speech. Wednesday morning, I was in the White House, trying to figure out how to merge the staffs and foster a less chaotic culture. And on Wednesday afternoon, I gave the interview that made me infamous.

I thought the interview was off the record. The journalist says it wasn’t, and at no time on the recording did I say affirmatively that it was. He went to CNN with the recording, and millions of people heard me say a lot of very excoriating things, laced with profanity, about Bannon and Priebus.

Everybody thought that’s why I got fired. It wasn’t. Trump thought what I said about Bannon and Priebus was funny. But other things I was doing irritated Trump.

By Friday morning Spicer’s been gone for a week, Priebus has just been fired and Bannon doesn’t have far to go. In a way, I’ve brought about what I came to do. Now I’m in the Cabinet Room with Trump, who is saying he wants to veto the Russia sanctions bill over election interference.

This is not the Russia-collusion issue. This is election interference, which everyone knows happened. The Republicans have passed the bill. I turn to Trump and say, “You can’t veto the thing.”

He says, “Why can’t I veto it?”

“Well, you’re here six months. This is your team that passed it – [Republican leaders] they passed the bill. They’re on your team. You veto it, they’re going to find 17 votes to overturn your veto.” (Note that the party wasn’t yet 100% Trump-GOP. There was still some possibility of pushback, from some Republicans, against some of his crazier ideas. That’s long gone now.)

He looked me straight in the face. “They can’t do that. I’m the president of the United States.”

“They can do that,” I said. Now we were doing eighth‑grade social studies. He picked up the phone and called the general counsel, Don McGahn. Probably as startled as I was that he had to explain it, McGahn confirmed that, with a supermajority, Congress can override a presidential veto.

Shortly after, Jared Kushner told me I’d embarrassed Trump and was probably going to lose my job, and at 6am on the following Monday, I knew it had happened. My encrypted White House iPhone wasn’t letting calls or texts in or out. At 9.30am, I was given the news by General John F Kelly, who had taken over from Priebus as chief of staff and been sworn in hours earlier.

He was a total gentleman, and clarified the situation.

“Well, there’s two things,” he said. “The president doesn’t want you here any more, so that’s reason enough for you to go. But number two, Anthony, just being honest with you, you were reporting directly to him. I’m the new chief of staff. If I kept you, all the papers would write about is that there are two direct reports to the president, and I can’t have that. I’m a four-star general. You’ve got to go.”

And that was the end of an 11-day fiasco.

I bombed so cataclysmically because I did not understand Washington. I was a complete amateur. I actually thought I was going to help change the world. It was pride, egocentrism and asinine stupidity. I missed the birth of my son. I almost lost my marriage. It’s all well documented. You can read a lot more about it if you want – some true, some not.

Deidre and I reconciled. Eight years later, we’re still happily married.

But that’s now. Go back to 1 August 2017: my wife and kids have left. I was shot out the door on to Pennsylvania Avenue, rolled in broken glass, skinned alive, seasoned with margarita salt by the late‑night comedians and the Sunday pundits. I’m on the front page of 40 global broadsheet papers. I became famous as an epic failure. Who could I blame? I was the victim of my own personal human folly.

I met with a crisis PR person that week to discuss damage control. The advice was that I’d completely disgraced myself and my career was basically over, at least for now. Since I had money, I should go to Tuscany, buy a villa and hide out for five years. Maybe after that I could come back and begin rehabilitating myself.

I didn’t take that advice.

I had a gut feeling that I had no choice but to work my minutes of unhappy fame as a royal screwup. I was in demand as a guest – the talkshow hosts had been raking me over the coals, and I was a main character. So I went on late-night shows – Stephen Colbert, Bill Maher. I went on the cable news shows. I owned what I thought I did right and did wrong, and I took a fair number of punches.

But I didn’t break with Trump. I was a lifelong Republican. I didn’t want to come off as a bitter jackass. I wanted to be FBL: Fired But Loyal. It was me who had done lots of things wrong anyway.

By 2019, though, I was finding it harder and harder to defend the president. I was still trying, but what seemed like constant policy goalpost shifting was giving me glimpses of what I hadn’t wanted to see.

Trump was exploiting the suffering of the people for his own narcissistic and malevolent ends. In August, on the Bill Maher show, when challenged by Catherine Rampell, then a Washington Post journalist, I said that as a child of immigrants I thought the president telling the women of [Democratic faction] “the squad” – Alexandria Ocasio-Cortez of New York, Ilhan Omar of Minnesota, Ayanna Pressley of Massachusetts and Rashida Tlaib of Michigan – to go back to the countries they came from was wrong (all but one were born here), a form of racism, and the kind of thing my grandmother had been forced to put up with, and that since Trump was the president, I wished he wouldn’t speak like that.

That one mild departure from my FBL mode brought out the malevolence in Trump. We got into a flame war on Twitter, which was entertaining and got attention, but under all the bluster I was finally realising how truly my judgment had been impaired. Trump was going to be very destructive to the country – and I’d supported and defended him. I was in need of a moral reckoning.

I had to separate from him. And he was the Republican president, so, more painfully for me, I had to separate from the Republican party, because he’d decapitated it. He’d picked a vulnerable major party, my party, and went after it and did a mergers-and-acquisitions transaction. Even as I was separating from the party, the rebranded Trump-GOP was magnifying itself. Guys like Henry Kissinger and Dick Cheney started leaving. And people like Marco Rubio started going all in. Can I understand how that happens? Yes. I got intoxicated by power. I went into Trump’s world for what I thought were the right reasons but were the wrong reasons. So that’s the story: a colossal series of errors in personal and political judgment.

But if I hadn’t gone through it, if I hadn’t been forced toward a moral and existential reckoning, I never could have arrived at the ideas about our country and our crisis that I have now. I’m more empathetic, more psychologically minded; I know myself better. I’m aware of the frailty of others – and my own frailty, too. I bought into Trump, and I almost lost myself.

This is an edited extract from All the Wrong Moves by Anthony Scaramucci, published by Bodley Head on 17 September at £25. To support the Guardian, order your copy at guardianbookshop.com. Delivery charges may apply. He is on tour in the UK from 14-19 September; tickets from intelligencesquared.com