Jamie Foxx portrays the troubled but gifted Nathaniel Ayers, left, and Robert Downey Jr. is Los Angeles Times reporter Steve Lopez in The Soloist.

Paramount Pictures / Francois Duhamel

Playing the Good Samaritan doesn’t always lead to the kind of happy Hollywood ending screenwriters might yearn for, at least when the script is based on real-life events.

That’s what Los Angeles Times columnist Steve Lopez discovered when he took under his wing a homeless man he found playing Beethoven’s music on a two-string violin at the foot of a Beethoven statue in a downtown park. Intrigued by Nathaniel Ayers’ lovely playing and his word that he once was a student at the prestigious Juilliard School in New York City, Lopez pursued Nathaniel’s story, thinking it would make an interesting column. What evolved from what at first was Lopez’s self-serving attempt to fill column space was a fragile relationship that was built up over months, several columns and eventually a book — The Soloist: A Lost Dream, An Unlikely Friendship and The Redemptive Power of Music. And now there’s the movie The Soloist.

It’s a lovely film that puts Lopez (Robert Downey Jr.) on a tightrope wire as he carefully tries to pick his way across the chasm to connect with the often-jangled mind of Nathaniel (Jamie Foxx). He’s frustrated as often as he’s elated and so, in Joe Wright’s tight direction, is the audience. As soon as Lopez thinks he has made progress in coming closer to Nathaniel, who has his clear-eyed lucid moments, something upsets the calm and Nathaniel takes a big step backwards.

He’s clearly a musical savant, who actually studied the cello to great promise until the voices in his head grew louder and sent him fleeing from Juilliard. When a reader of one of Lopez’s columns is moved by Nathaniel’s story and his two-string violin, she sends him her prize cello and he creates beautiful, mournful music with it.

But Nathaniel is also, to say the least, mercurial. Foxx makes him both a sympathetic character and one who is frustratingly difficult. Foxx’s performance walks the tightrope as well, between hopeful and hopeless. He speaks in rapid-fire chatter, often straightforward and intelligent, sometimes in mixed-up gibberish. Dressed in outlandish clothes, hauling his only possessions through the streets of Los Angeles in a shopping cart, lost in his own world, Nathaniel plays to no one but himself in a busy auto tunnel because he likes the acoustics.

It is from this that Lopez hopes to “rescue” him, to find the key that will unlock the secrets that he’s certain are holding Nathaniel back from “normalcy.” It is not an easy path. Nathaniel’s story seems to become Lopez’s only story as he hunts down Nathaniel’s long-estranged sister and explores his past in hopes of discovering what made him the man he is today. In flashbacks we follow Nathaniel’s tale from age 11, living in a rundown neighborhood, to Juilliard, where those voices eventually drive him away from his studies.

There’s a moment in Nathaniel’s youth which Wright, whose previous film was the magnificent Atonement, stages with haunting eeriness — Nathaniel peers out his window to see a flaming car roll down the street a block away. As the flames consume the car in the background, young Nathaniel plays his cello with passion.

Making Nathaniel his good-deed “project,” Lopez coerces him into entering a Skid Row center that provides shelter and comfort to the destitute and mentally ill homeless. Lopez’s drive into the center’s neighborhood is an eye-opening trip into some weird parallel universe with down-and-out characters that seem closer to the slums of Calcutta than to the glitz of Los Angeles and Beverly Hills, even though those places are only a few miles away. It is a modern-day vision of hell.

Downey plays Lopez with understanding and compassion, carefully prodding Nathaniel into bringing his promise to fruition. One can readily identify with him. But Lopez’s best intentions are often, surprisingly, upended by Nathaniel’s sudden leaps into chaos. Trying to make a connection proves to be like walking into a minefield. Lopez assures himself that he is trying to help a gifted man who had lost his way, but realizes only much later that there is much more to Nathaniel’s problematic makeup than something as simplistic as good intentions will solve. Audiences at the start might expect some Hollywood miracle to eventually occur, but the screenplay by Susannah Grant (Charlotte’s Web, Erin Brockovich, Ever After, Pocahontas) does not invent good tidings where there are none. Nathaniel is a difficult subject who refuses to be pigeonholed.

While Lopez focuses his attention on Nathaniel, the world doesn’t stop turning. There’s a sort of tentative relationship between him and his editor (Catherine Keener, very assertive) and, in the background, the slow unraveling of the Times itself. A reporter carps about fluff “news” that gets more reader response, the paper’s loss of circulation, the fact that fewer young people read newspapers. Employees leave the paper through buyouts and layoffs. In one scene Lopez and his editor discuss a story while, behind them, a reporter flanked by a pair of burly security guards is led out of the building carrying a plant and a box of her personal possessions. It’s a sobering background to what is a touching story.

****The Soloist

Starring: Robert Downey Jr., Jamie Foxx, Catherine Keener, Stephen Root, Tom Hollander.

Rated: PG-13, contains violence, profanity.

‘Soloist’ star Robert Downey Jr. is a shape-shifting chameleon1

In the past year, Robert Downey Jr. earned a reputation as one of Hollywood’s most versatile stars, playing alcoholic, egocentric superhero Tony Stark in Iron Man and half-mad method actor Kirk Lazarus in Tropic Thunder.

Now, in The Soloist, opening Friday, Downey portrays a real-life person: Los Angeles Times columnist Steve Lopez, who discovers a homeless, schizophrenic musical prodigy (Jamie Foxx) and begins an unlikely friendship that changes both men’s lives. Lopez, divorced and cynical about emotional relationships, learns the value of simply showing up consistently and trying.

It’s a point that Downey has learned from personal experience as he rebuilt a career derailed by repeated battles with substance abuse. In 1993 he was an Oscar nominee for Chaplin, a big-budget biography of screen legend Charlie Chaplin. From 1999 to 2000 he lived the role of inmate No. P50522 at a California prison. Since his release, he has been one of the hardest-working actors in the industry, finally winning a second Oscar nod this winter for Tropic Thunder.

His personal and professional rehabilitation seemingly complete, Downey has become a star that studios build blockbusters around. Whether the story calls for comic-book heroics, over-the-top comedy or inspiring drama, he demonstrates a shape-shifter’s ability to get beneath a character’s skin. His reluctance to be pegged led him to another offbeat role for his following project, a period English mystery in which he’ll star as a two-fisted, macho Sherlock Holmes.

We caught up with the ever-unpredictable actor last week by phone at his home in Los Angeles.

Q. Your dad was one of the wildest maverick directors of the 1960s indie movement, the man behind satirical cult classics like the advertising agency farce Putney Swope. What was it like growing up around that kind of iconoclasm? How did that set you on your course?

A. It’s everything, honestly. I have Putney Swope on my iPod. Sometimes I’ll watch it and just go, “My God, what crazy stock I’m from.” And what a blessing, you know?

Q. I imagine it gave you a pretty robust B.S. detector for the business you graduated into.

A. Yeah. And some of that is around-the-blockdom. You know, this is my silver anniversary of doing this, and it’s really starting to get interesting.

Q. There are only a handful of actors like Johnny Depp and you who can navigate a long career and yet consistently stay fresh. What’s the secret?

A. Oh, gosh. It must be my new depilatory cream. Honestly, if you stay engaged it stays engaging. There you go.

Q. In your new film you and Foxx both play radically isolated characters. In your mind, who’s the soloist of the title?

A. Joe (director Joe Wright, whose last movie was Atonement) would say he first thought it was Jamie and then realized it was me. We would all say we thought the film was about friendship and about mental illness. But we all now say the film is about faith. That’s what makes things interesting. I love the theme.

Q. The film is full of reminders that homelessness could happen to anybody. Katrina could hit your town, you could fall off your bike and lose everything, you could be laid off, and next thing you could be living out of a shopping cart.

A. Yeah, and hopefully once that’s a foregone conclusion, can we now have empathy? In that scene with Steve and his wife (discussing life’s unpredictability), I said, “I think he should start talking about the Northridge quake.” Because the Northridge quake was a Los Angeles event at the time they had moved here, and had all the promise in the world of their marriage and their careers and their futures being forever entwined and beautiful. And something quite different happened. In fact, his only friend now is somebody who is a stranger to himself.

Q. And in the process, your character discovers a hidden spring of empathy in himself.

A. That sense of having true empathy and compassion is realizing not just “There but for the grace of God go I” but also, even with our contradictions and traumas and shortcomings and things that are remiss and regrets, that we all have the fortune to operate in a fundamentally sane realm. The idea of being forever uncontained is such a wrenching prospect, and yet there are still ways we can connect with each other, and embrace.

Mel Gibson has a fantastic phrase: “You gotta hug the cactus.” I think that’s what it is. Faith that there’s value in hugging the cactus. It’s a necessity. It’s unavoidable.

Q. What are the rewards of playing a kind of anonymous guy like Steve Lopez as opposed to iconic characters like Chaplin, Iron Man and Sherlock Holmes?

A. Steve Lopez and I were basically conjoined twins. And together we created a personification of the best principles we can demonstrate. There’s no movie if he doesn’t have a moral psychology. So I look at Steve Lopez and see that he is a good guy. Is he an entirely enlightened person? No. But is this relationship the thing where he interfaces with that possibility? Yes. So you’re playing that rather than: He has hair like this, speaks like this. Oh, it was a tough gig.

Q. What made it tough?

A. I was there (at L.A.’s shelters). I bore witness to it every day. I was the guy on-site, on my feet 12 or 14 hours a day. And a lot goes down in that movie. There’s a lot of karma there.

mjanuson@projo.com