Matt Damon, in a surprisingly nuanced performance, plays fledgling attorney Rudy Baylor, a modest, polite-spoken young man who has barely graduated from “Memphis State” when he lands a whopper of a case: a family wants to sue the Great Benefit insurance company for denying a bone-marrow transplant to their leukemia-stricken son. Penniless himself, he takes a job with sleazy lawyer Bruiser Stone (Mickey Rourke), whose office is next to a topless club (Danny’s, which is not disguised for the movie). Rudy is homeless, too, so he rents a carriage house on the property of flighty Midtown widow Miss Birdie (79-year-old Teresa Wright), who turns him into her “yard boy.”

Rudy takes everything that’s thrown at him and doesn’t complain. He seems too good to be true. He also seems more than a little wet behind the ears, but we know from his sardonic voiceovers that he’s aware of the absurdity of his situation; he just doesn’t yet have the power to control his own destiny.

With prodding from “paralawyer” Deck Shifflet (Danny DeVito), Rudy goes into business for himself and sets about confronting Great Benefit’s army of lawyers. When he faces them all across a boardroom table, it truly is a David-and-Goliath scenario, and the kid scores with a verbal slingshot. His nemesis is the insurance company’s chief lawyer Leo Drummond, played with arrogant self-righteousness by Jon Voight. Slick and superior, Drummond can scarcely contain his mirth at Rudy’s ignorance of courtroom procedure. But through some not-quite-illegal maneuvering, Deck and Rudy manage to expose a weakness in the insurance company’s armor.

In the midst of all this, there’s a parallel story in which Rudy plays the gallant hero, rescuing a damsel in distress. He meets Kelly Riker (Claire Danes, who doesn’t have much to do except look hurt), a young woman who has been repeatedly beaten by her husband but who is afraid to leave because he’s threatened to kill her. Instinctively Rudy wants to protect her, and theirs is a sweet little tale of blossoming love, with Rudy as the pure-hearted savior. It’s tangential to the main plot, yet directly connected to the movie’s theme: There’s right and there’s wrong. Domestic violence is wrong, and Rudy won’t stand for it. (The movie might be a bit more interesting if Rudy were ever tempted to the dark side, but on the other hand, it’s refreshing to see someone so steadfast in his principles.)

This all sounds pretty heavy-handed, but it doesn’t play that way. This is by far the funniest Grisham movie ever, thanks in large part to DeVito’s indefatigable antics (as Deck, the unrepentant ambulance-chaser who’s failed the bar exam six times, he hands out business cards to anyone with visible evidence of injury). And Coppola, who also wrote the screenplay, inserts a number of witticisms into the script.

As director, Coppola pulls excellent performances from all of his cast members. In contrast to most Grisham adaptations, which are full of stereotyped characters and outlandish plot devices, Coppola makes this one a human story – a collection of quiet moments between people who seem true to life.

For example, Red West, as the brain-addled (“he’s got a plate in his head and he ain’t right”) father of the leukemia patient, could have played his mental deficit for laughs. Instead, he creates what may be the most emotionally powerful moment in the whole film, and he never says a word.

Coppola’s sharp judgment in picking actors extends to his choice of production staff as well. His director of photography is John Toll (Oscar winner for Legends of the Fall and Braveheart), who depicts Memphis honestly without glamorizing it (as The Firm tended to do). Memphians will easily recognize many of the sites, from Court Square and the Pinch district to The Med and the Shelby County Courthouse. (And the Las Savell jewelry store gets priceless free advertising.)

But with Coppola’s insistence on using real locations, it’s puzzling why the film refers to the University of Memphis by its old name. Grisham set the novel before the university’s name change took place, but since the film moves the action up to 1996, “Memphis State” is an anachronism.

The other thing that elicits groans from local moviegoers is the reference to “Union Street.” With all the Memphians who were involved with the production, you’d think somebody would have caught this egregious flub. And The Rainmaker, despite its visual authenticity, resembles every other Grisham film in one respect: Its characters speak with syrupy, Hollywoodized Southern accents. I’ve been here all my life and don’t talk that way, nor does anyone else I know. Why didn’t the dialogue coach listen to some actual Memphians?