It’s fair to say that Ben Affleck’s career has tended to – in the words of Morrissey – oscillate wildly.

While there were commercial and critical successes like Armageddon and Shakespeare In Love, there were also infamous flops, such as Bounce, Gigli and Daredevil. As well as getting Affleck some of the harshest criticism of his career, each of those films also introduced him to the three great, high-profile, and ultimately failed loves of his life: Gwyneth Paltrow, Jennifer Lopez and Jennifer Garner.

The actor’s personal life is again in some turmoil following his split from Garner, but his roles in Gone Girl, Batman V. Superman: Dawn Of Justice and now The Accountant are marking a new phase in his acting career – and the 44-year-old is grateful for it.

“I’ve gotten to be much better at recognising my luck as I’ve got older,” says the actor, his tall frame filling an armchair in an LA conference room. “I have three great kids, and they’ve got the best mom in the world, and I’m really lucky that I get to work in this great business. I look around my life, and while everything’s not exactly how I want it to be – every take isn’t perfect, and I’d like there to be world peace, and I’d definitely like the political situation to be different than it is – I can see how lucky I am. That’s an important thing to remember. And people are bad at that in this industry. My brother has this joke,‘What’s the best way to get an actor to complain? Give him a job.’”

But there’s not a complaint in sight as Affleck promotes his role in The Accountant. In Gavin O’Connor’s witty thriller, Affleck plays Christian, a man with Asperger’s Syndrome who works as a do-gooder accountant by day, but crunches numbers for criminals and cartels at night. When he uncovers a major fraud, he becomes hunted – but his martial arts skills and ruthlessly efficient violence make him a formidable enemy.

While the film is a gritty thriller, it’s also a character study, as the story reveals how Christian’s father tried to protect his son by forcing him to learn how to fight. The movie avoids the usual trope of the desexualised character with autism, exploring Christian’s attraction to charming accounting clerk Dana (Anna Kendrick), and his desire for connection.

“The movie was about two things for me,” Affleck reflects. “One was about parenting and children and the way we try to protect our children, even though we may be doing damage. That hold that we have over our children and that they have over us was really interesting to me. But I also liked the idea that all of the rich meaning in life can be found through relationships. All that is valuable and good in life comes from our connection with others.”

Affleck admits that his knowledge of autism and Asperger’s Syndrome was limited to other pop culture representations, such as Rain Man, The Curious Case Of the Dog In The Nighttime, and the controversial vaccine debates. So the actor took it upon himself to do serious research. “I did a lot of reading,” he explains. “I also talked and visited with people on the spectrum, who knew upfront that this was research. People were very open and willing to share and talk about their experiences of family, of love, of stigma. I think people were so open because they wanted to be understood, and that if someone was to do a representation of Asperger’s or autism or the spectrum – there’s even still debate about the language – they just really wanted us to get it right.”

The actor is quick to diminish sweeping stereotypes or assumptions about the condition, and claims he didn’t base his character on any one person. “There is no one universal experience,” he notes. “So it was about picking individual truths from people. It remains very mysterious to me – I didn’t come away from my research with this complete understanding of autism, because everyone’s experiences and challenges are different. But I did come away with this humanist sense that we are far more alike than we believe, because we’re all ultimately looking for connection, and some people with autism find that harder than others. But that want is still there, that want to have a relationship, the want to have a friend, the want to communicate. That was what was really moving about the research.”

The action in The Accountant has the slick, polished grit of pal Matt Damon’s Bourne franchise. But it also has the atmosphere of classic Hollywood conspiracy thrillers, an influence Affleck is quick to acknowledge.

“This movie has a nicely ‘70s feel to it,” he remarks. “It’s thoughtful, it’s shot on film, it has a grittiness to it. You can look at the likes of Three Days Of The Condor or The Parallax View – some of those sweeping, cerebral thrillers of the ’70s, and see some overlap and influences there. I’m attracted to projects that are like movies that used to be made more commonly. There are fewer and fewer categories of movies handled by studios – you’re tasked with finding someone to give you money and then maybe you might get distribution. Otherwise, it’s a superhero movie or an animated movie or a high-concept movie or gross-out comedy. But Warner Bros are great in that they’re a filmmaker’s studio, and they’re committed to seeing talented people express their vision.”

It’s convenient that Affleck’s love of Warner Bros also allows him to play Batman in their current Justice League franchise, but he does seems genuinely enthused about donning the cape (he’s getting ready to direct and star in The Batman). He also appreciates that the new Batman tales are exploring the cost of being a hero.

“Movies that explore those juxtapositions are intriguing,” suggests Affleck. “Asking these thorny, uncomfortable questions comes from our growing awareness of a more complicated world. We’ve evolved past ‘Faster than a speeding bullet!’, and now ask ‘What would happen if you were more powerful than a locomotive? That would probably fuck you up – you might have some issues and you’d need some therapy!’”

He pauses. “It’s this post-modern awareness that good things in life often carry a price with them.”

He would know.