Bryan Cranston excellent as ‘Trumbo'

Sitting in a bathtub with a pen in one hand and glass of whiskey in the other, a long cigarette holder dangling beneath his wiry moustache, Dalton Trumbo wrote countless Hollywood screenplays.

From B-movies to Oscar winners, he remained prolific throughout his career, even during the 13 years he was blacklisted by the movie business for being a communist.

He went to prison for holding fast to his ideals - that Americans have the right to believe as they please without retribution from the government - and upon his release, he worked constantly and defiantly, but at significant personal and professional cost.

But you don’t have to know a thing about Trumbo, Hollywood or communism to enjoy watching “Trumbo.” A biopic lovingly rendered with input and approval from his daughters, “Trumbo” is about an idealistic yet imperfect man who stands up for what he believes is right, even when it means risking the things he holds most dear.

The script is funny and fact-filled; the acting outstanding.

As the title character, Bryan Cranston gives a performance as compelling and complex as the man himself must have been. Cranston’s Trumbo is eminently interesting, from his rounded posture and curious eyes to his distinct cadence and diction.

Appearing in nearly every frame of the film, Cranston infuses John McNamara’s clever screenplay with even more life. With a vocabulary of witticisms, Trumbo speaks like a man who loves language.

The ensemble of supporting actors is also excellent. As Trumbo’s wife, Cleo, Diane Lane embodies quiet strength, conveying heartbreak, pride and concern with just her eyes. Louis C.K. plays Trumbo’s fictional friend Arlen Hird, who delivers sharp one-liners and clever retorts just like the comedian himself might.

Dean O’Gorman is uncanny as Kirk Douglas, right down to the chin dimple. Michael Stuhlbarg brings the necessary gravitas as actor Edward G. Robinson. Helen Mirren’s grounded performance keeps the outlandish gossip columnist Hedda Hopper from becoming a caricature.

And John Goodman absolutely steals his scenes as B-movie producer Frank King. Watching him smash up his office with a bat and explain what keeps him in the movie business is alone worth a trip to the theater.

Director Jay Roach (“Game Change,” “Meet the Parents”) keeps these big performances of even bigger personalities in balance, an oscillation of stars around Trumbo.

The story begins in 1947. Trumbo, a labor-union supporter, would regularly meet with his friends - Hird, Robinson and other Hollywood colleagues - to discuss political and social ideas. Like many others, Trumbo had become a communist after the Great Depression, and the group was concerned about the state of the country.

As Louis C.K. describes it: It was “kind of like blogging, but they did it in person.”

The U.S. government, meanwhile, was concerned about the rise of communism, and thought movies were one way communists conspired to control American minds. The House Un-American Activities Committee called on Trumbo and other artists to testify about their political beliefs and identify colleagues who might be communists.

Trumbo declined to name names, and said his right to peaceably assemble and share ideas is protected by the Constitution. He was held in contempt of Congress and spent a year in jail. Others in Hollywood did name names, and those believed to be associated with communism were suddenly indefinitely unemployed.

The industry policed itself through the Motion Picture Alliance for the Preservation of American Ideals (which sounds fake, but wasn’t). John Wayne (David James Elliot) was its leader, and gossip columnist Hopper its unofficial enforcer.

By combining archival footage with shots of the cast, Roach effectively inserts them into history, lending a sense of realism to the events.

It all makes for an enthralling story about how far government, industry and individuals might go to uphold what they believe is right.