“Storytelling is magic,” Jason Isaacs said. “It’s sleight of hand, it’s delivering a surprise ending that people don’t see coming.”

Isaacs, 61, best known for playing villains in “The Patriot,” “Peter Pan” and the Harry Potter films, was speaking via video call a few days before “The White Lotus” Season 3 finale. A keen amateur magician, he had already performed a couple of onscreen card tricks. His work on “The White Lotus” is also a kind of conjuration.

He plays Tim Ratliff, a Durham, North Carolina financier. Tim’s blood runs blue, as do the letters on his Duke T-shirt. (Duke is reportedly upset at the association.) Confronted with past malfeasance and facing the loss of all he has inherited and worked for, Tim spends his Thai vacation overdosing on his wife’s benzos and contemplating murder-suicide. That he can make Tim engaging even in the sweaty maelstrom of an entirely internal crisis speaks to his actorly gifts.

Not least among them is a way with misdirection. (Spoilers start now.) In Sunday’s season finale, Tim sets out to poison his family with a fatal batch of piña coladas only to change his mind a sip or two in. (Even his youngest son, Lochlan, played by Sam Nivola, who later took a dose via a protein shake, was spared.) Though Tim had spent the whole of the season running from his fate, he ultimately accepted it and trusted that his family would accept it, too. So that’s a nice surprise.

Isaacs, of course, knew this from the start. “I read all the scripts,” he said. But watching the finale with his castmates on Sunday, he felt strangely moved. “We were all of us holding each other’s hands and watching and crying our eyes out in a rather embarrassing way,” he said.

In a lengthy chat before the finale and a rushed one just after it had aired, with Isaacs still wiping away tears, he discussed villainy, accents and the awkwardness of onscreen nudity. These are edited excerpts from the conversation.

Why does Tim ultimately decide not to poison his family?

Because he looks at them and he realizes how much he loves them. The actuality of it breaks through the fog of the drugs and terror and catastrophe that had been filling his head for so long. In that moment, he loves them more than he wants them to die.

The title of the finale, “Amor Fati,” references the Nietzschean concept of accepting your fate, which is maybe not so different from certain Buddhist teachings. How does that resonate with Tim?

I think he accepts it completely. Ironically, of all the characters who arrive in Thailand, he’s the one that becomes closest to those Buddhist principles. He gets massive spiritual enlightenment.

Is Tim a villain for most of the season?

What’s a villain? Tim is Tim. He did a deal that went wrong. It was technically illegal. Many people do illegal things all around him, I’m sure. It wasn’t even a big deal to him. Is he a villain when he fantasizes about killing his family because he thinks that’s an easier way out for them, because of the shame that he knows he’s going to face? I think any talk of villains around Mike White’s writing is to misunderstand how humanist he is as a writer.

So Mike created this character of a Southern hedge fund guy in a full existential meltdown. And apparently he thought of you.

Actually they thought of someone else first. He said, no, thank God. [Isaacs didn’t name the other actor.] I had to audition, which was an odd thing for me. I find auditions stressful. I went into a room and bumbled and stumbled and stuttered in front of a video camera. I was thrilled to get the job. Then they sent me the scripts and that gave me pause. Because here was a man who was out of his head on drugs that make you soporific. I had no idea if I could make that interesting. Or communicate to the audience what must be going on in Tim’s head — the panic and the terror and the reputational damage and that existential angst.

I’d spoken to my brother, a psychiatrist, and asked what the effect of chugging Lorazepam all day would be. He went, “You would be asleep.” I went, well, that’s not going to fly on television. Mike was both reassuring and not. He said, “Let’s just have an adventure together; we’ll come up something. I won’t let you be boring.”

To prepare, I understand Mike had you watch “Southern Charm”?

Mike directed me to have a look at one of the characters in “Southern Charm.” I did. Also, I was starting to do sessions with Liz Himelstein, who’s one of the great dialect coaches. I knew he was from Durham, and Durham has a rather peculiar accent. It’s a hangover of the old colonial days. Young people don’t do it. Old people do it. Someone like Tim, who wanted to sound like his grandfather, he would. It’s been hard for me, as someone who loves accents, to see people online who don’t know anything about Durham say, “He doesn’t sound Southern.” The accent’s right. Hearteningly, lots of people from Durham love it.

Did you see that Duke is upset that Tim wears Duke gear?

I thought that was rather hilarious. If you wanted to bring the university in disrepute, there are real life alumni from who do far worse than Tim Ratliff. But there goes my honorary degree from Duke.

Why can’t Tim confide in his family as he is falling apart inside?

Because what are you going to confide? Our life is over, as we know it. We are all going to be broke and poor. We won’t have a house, a car, a phone. I will be in prison. Our family name will be in tatters. I mean, it’s unimaginable to him.

This is a man who’s always been able to fix every problem, because no problem was so big that money and power couldn’t crush it. But there is no way out of this. He just is trying to obliterate his brain. He’s trying to get himself as close to a coma with the pills and the alcohol as he can. Those drugs, for most people, they make you relaxed. For Tim, these drugs are not working. He gets no peace.

How do you act that?

Because we shot completely out of order, that was my particular job, to work out how out of his head he is at any point. I needed to have my head exploding with terror and yet layer on top of it a drug that was trying to blur things. I do whatever prep I can, research, accents. Then I just try and be that person. I don’t know what acting is, and I don’t know how I do it. It’s an animal instinct.

You described this shoot recently as “Lord of the Flies” in a gilded cage? Did you turn feral?

We were sticking pigs every day. No, but it wasn’t entirely blissful. Obviously people formed friendships, but we weren’t one great big homogenous happy family. It was a large group of people away from home, unanchored from their normal lives. I’m not going to break ranks and say who did what to whom, but it certainly wasn’t a holiday.

How did it feel to do nudity at 61?

Oh, I have no idea. I can’t even think about it, let alone talk about it. Sex is embarrassing; nakedness is embarrassing. It’s embarrassing at any age. But it’s harder to be heartbroken, terrified, homicidal, suicidal — to be at the edge of life and think that I would be better not existing. Taking my clothes off is just a physical thing. I mean, it’s as horrible and awkward as someone asking me to get naked in the street. But it’s all part of the job.

Has playing Tim made you think about your own family, your own fate?

I didn’t need “The White Lotus” to make me think about those things. I think about them constantly, particularly as my children grow. It’s impossible not to think about, as a parent and as someone getting older, being aware that you’re closer to the end than the beginning.

Will Tim ever stay at a White Lotus resort again?

I doubt he’s going have the resources. I think he’s going to be completely wiped out, which at that moment feels OK to him. He’s looking forward to being a member of the human race and not feeling like he needs to be better than anyone else. When he looks at the water, right at the end, the water flying in the air and joining the ocean again, there’s some part of him that feels less alone than he’s ever felt.