Their words were tools of social change

“TALK to Me,” which stars Don Cheadle and Chiwetel Ejiofor, hearkens to another era, to a time before shock jocks bestrode morning drive time like colossal blowhards. Cheadle plays Ralph Waldo “Petey” Greene, an ex-con turned Washington, D.C., radio and television talk-show host, beloved local icon and Howard Stern role model. Ejiofor plays the straight-laced Dewey Hughes, who put him on the air when nobody else would have. Their unlikely friendship and partnership, founded on a shared commitment to speak out against injustice, is the focus of director Kasi Lemmons’ film, which observes the fervor of a bygone activist culture longingly, as if to ask, what’s with everybody now?

Greene and Hughes met in 1966 at the Lorton correctional facility, where Greene was serving a 10-year sentence and Hughes was paying regular visits to his brother Milo (Mike Epps). As part of a work program, Greene had been allowed to host a show from the prison radio station and discovered he had a talent and passion for it. Hughes was then the program director for KWOL, a small, D.C.-based R&B; radio station.

Eventually, Greene talked his way out of prison early, talked his way into a job as a morning-show host at KWOL and, after blowing his initial shot, commandeering the airwaves under threat of arrest. Whether these events transpired as depicted -- flamboyant displays in the reception area, locking station manager and morning show DJ in their offices -- is open to interpretation, but the upshot was that Hughes cemented his position in the business and Greene established himself as the voice of the “other” Washington, D.C., a beloved and galvanizing figure in the community.

Most of the action of the film takes place in the late ‘60s and early ‘70s (Greene died of cancer in 1984) against the backdrop of the civil rights and antiwar movements, and Lemmons (“Eve’s Bayou”) makes liberal use of protest and riot footage, occasionally using it as a literal backdrop for Greene’s on-air riffs.

Part of what drew Lemmons to her subject was the contrast between Greene’s uncensored candor, emblematic of the era, and the mealy mouthed timidity of today, so you don’t begrudge her the occasional image mash-up, hammy though they sometimes are, or even the way she drives the message home at the movie and then walks it to the door.

Mostly, Lemmons and screenwriter Michael Genet (Hughes’ son) focus on the passionate and volatile friendship between Greene and Hughes, which Cheadle and Ejiofor (who have yet to make a false move between them) bring vividly to life.

Other characters, such as Greene’s flamboyant girlfriend Vernell (Taraji P. Henson) and station owner E.G. Sonderling (Martin Sheen), are appealing but one-note, though Cedric the Entertainer and Vondie Curtis-Hall make funny, note-perfect appearances as the velvet-voiced, “quiet storm” late night DJ, Nighthawk, and the ousted chipper morning-show guy, Sunny Jim, respectively.

But this is a love story, after all, so it makes sense that the others would recede indistinctly into the background. Cheadle’s Greene is as heavy-lidded, mercurial, self-destructive and free-spirited as Ejiofor’s Hughes is alert, focused and disciplined. Convinced at first that they have nothing in common, they eventually bond over their shared roots and commitment to the cause, and the marriage of their particular strengths creates something new and strange. If Cheadle and Ejiofor’s command of the characters is compelling and precise before the friendship takes hold, it takes on another dimension afterward as we come to see them through the appreciative eyes of the other.

The odd-couple relationship adds another layer as a lively argument on identity politics. The ongoing debate between Hughes and Greene also seemed to encapsulate a moment in African American history when identities were being redefined and roles debated.

Like Greene, the straight-laced, be-suited Hughes grew up poor and disenfranchised, seeing his older brothers go to prison. Unlike Greene, he put himself through school hustling pool and studied poise and carriage under the nightly tutelage of Johnny Carson. If Greene was outrageous and impolitic, fearlessly speaking out against poverty and racism, the restrained and polished Hughes worked effectively within the system, making it possible for someone like Greene to get on the air in the first place.

With its R&B; soundtrack and footage of civil unrest, “Talk to Me” might seem to cover familiar ground. But as an intimate portrait of the complex, fruitful and extremely volatile friendship between trailblazing African American men whose daring came to redefine an industry, it’s fresh and revelatory.

carina.chocano@latimes.com

“Talk to Me.” MPAA Rating: R for pervasive language and some sexual content. Running time: 1 hour, 58 minutes. In selected theaters.