Before becoming the only screenwriter to script back-to-back best pictures (2004's "Million Dollar Baby," then "Crash," which he also directed), Paul Haggis was in the dumps.

He came to Los Angeles in his early 20s from southern Ontario, the grandson of a janitor and son of a road-repair contractor. He had a couple of decades of hit-and-miss TV work, writing for "Diff'rent Strokes" and "Facts of Life," envying friends who wrote prestige shows like "Cheers."

He pitched dark, questioning original projects to executives who wanted clear, uplifting stories. He confronted his subpar output when he was fired from his own show ("Family Law") in 2001. Then he poured himself into provocative screenplays about euthanasia and class divisions, issues he had personal experience with, scoring the biggest successes of his career.

So Haggis is well-positioned to make a film about a conflicted writer worried that his time is up. That's Liam Neeson's role in "Third Person," Haggis's multi-character story (opening Wednesday) about relationships in Paris, Rome and Manhattan imperiled by the loss of trust. It's a theme that also implicitly reflects Haggis' messy romantic and marital history. Whom can you trust with your trust?

A story can't succeed "unless you dig deep enough, unless you're honest enough," he said by phone recently. "I had a woman I was in love with who said, 'I'm never going to open up to you. I'm never going to be vulnerable to you. The moment I do, when I am truly vulnerable to you, you will betray me.' I thought, 'This was a woman with serious trust issues. But what if she's right? What if it's all just a game?' 

"I have so many questions about love. How do you win at it? Especially if you're in a relationship with an impossible person? What if you believe in someone who's completely untrustworthy, who at their core can't even believe in themselves? If you damn them, do we win that way? If you just keep investing in them, do they become what we imbue them with, do you win then? It's a very romantic notion, but it might work." When Haggis went through such an affair several years ago, it capsized his own marriage before flaming out.

Despite a cast including Adrien Brody, Mila Kunis, Maria Bello, Kim Basinger and James Franco, getting the story to the screen was a challenge. The film's financing came from Europe, where there's a long history of adult ensemble dramas.

"This was a strange amalgam, an American film at its core but very influenced by the European filmmakers of the '60s and '70s, like Antonioni's 'Blow-Up.' " Haggis said. "It's a murder mystery, but there's no solution, and it ends with a tennis game between mimes. You leave the theater thinking, 'What the hell was that about?' but as you argue it out you get a deeper understanding of what it's about. That was the kind of film I wanted to make, and you're not going to get that financed by studios."

But they're the kind of movies that made Haggis fall in love with films. He grew up in the small city of London, Ontario, not far from Detroit. It wasn't a place where there was a lot of great cinema in the local theaters, so he started his own film society at 19, screening films that sounded interesting in the catalog.

"That's where I found out about Pasolini, Bergman and Fellini. I watched and thought, 'My God, can you tell a story like that?' That always stuck with me. It's why I wanted to make a film like this."

The film also concerns children at risk, a cause that absorbs much of Haggis' time between film projects. In 2008, he founded Artists for Peace and Justice, a nonprofit that assists Haitians through programs in education and health care.

His interest began when he learned of the humanitarian work being done by doctor and priest Father Rick Frechette. Haggis, who was raised a Catholic, became an atheist and then for 34 years a prominent Scientologist before leaving the organization in 2009, decided they had to meet. He flew to Port-au-Prince and stayed with Frechette as he worked in the slums for a week. "I was so impressed with what he could do with so little," he recalled. "I couldn't walk away from that, so I started this organization and pulled my friends into it."

Leveraging his celebrity connections, Haggis secured sponsorship commitments from luxury brands, including the Swiss watchmaker Bovet, which recently pledged $4.5 million to the cause.

Haggis' organization is dedicated to empowering local workers rather than imposing solutions from outside. "That's the neocolonialist attitude. 'We know what's best for you and we'll take care of this.' Straight up charity. This is not that." APJ began by sponsoring a high school for 120 students, "the poorest of the poor." Four hundred kids turned up the first year, so APJ tripled the size of the school, and will expand again to accommodate 3,000 kids within the next two years.

"I get down there as often as I can," Haggis said, and he spends time advising students at another AJP facility, a film and audio engineering school. "The graduates are earning 20 times what their parents ever did. And in the arts! Here you go through film school and you struggle to find a job. Down there, you can get a job."