Jackie Robinson was the ideal class act to break the barrier and become the first black player in Major League Baseball.

Writer-director Brian Helgeland’s Robinson biopic "42" is a class act itself, though not always an engaging act. It’s such a familiar story that any faithful film biography almost inevitably will turn out predictable, even a bit routine.

With an earnest performance by Chadwick Boseman as Robinson and an enjoyably self-effacing turn by Harrison Ford as Brooklyn Dodgers boss Branch Rickey, "42" hits every button you expect very ably. It riles with its re-creations of the heartless, ignorant racism to which Robinson was subjected. It uplifts with its depictions of Robinson’s restraint and fortitude. It inspires with its glimpses of support and compassion from teammates and fans.

Yet like a sleepy, low-scoring ballgame, "42" is not the jolt of energy and entertainment we wish it could be.

‘42’ Rated: PG-13 Opens today

Unlike No. 42 Robinson’s daring on the base paths, "42" plays out safely and methodically, centering on the two most critical years in his rise to the majors and letting that time unfold with slow, sturdy momentum.

The film starts in 1945 with Boseman’s Robinson among many great talents stuck in the Negro Leagues because of the whites-only code that rules the majors. Rickey, played with crusty, jowly curmudgeonery by Ford, is scanning the black rosters, determined to find the right mix of skill and temperament to make a mark in the big leagues — and withstand the certain firestorm of bigotry with grace and self-control.

Robinson is Rickey’s clear choice. "I want a player who’s got the guts not to fight back," Rickey tells Robinson. "Your enemy will be out in force, and you cannot meet him on his own low ground."

By spring 1946, Robinson had secured a spot on the Dodgers’ minor-league team in Montreal. As eventful as that season is — with white fans booing Robinson, opponents taunting him and police in the Deep South insisting he can’t play on the same field as whites — it’s only a warm-up for what comes in 1947 after Robinson dons a Dodgers uniform and steps out of the tunnel at Ebbets Field.

Some of his own teammates already have balked at playing with Robinson, a rebellion quickly quelled by Dodgers manager Leo Durocher (Christopher Meloni, in a small but delightful performance).

There are death threats, savage verbal abuse, pitchers deliberately aiming to bean Robinson, hotels that turn away the entire team because of his presence. Alan Tudyk takes on an ugly role and delivers perfectly as Philadelphia Phillies manager Ben Chapman, who mercilessly hurls racial slurs at Robinson each time he comes to bat.

It’s that sort of hatefulness that stirs and shames others into acts of decency. As Dodgers shortstop Pee Wee Reese, Lucas Black gets to re-enact a classic baseball moment, when he responds to a jeering Cincinnati crowd by throwing an arm around Robinson’s shoulders and standing shoulder to shoulder with his teammate for the world to see.

The filmmakers show nice restraint in the baseball action, focusing on Robinson’s sneaky, speedy base-running rather than laying on montages of towering home runs. Boseman resembles Robinson physically, and he clearly put in his time at training camp to imitate Robinson’s unique batting and base-stealing styles.

Ford and Boseman bond to present a big-hearted friendship between Rickey and Robinson. With a slouchy mix of dapper but rumpled elegance, Ford is a pleasure to watch and especially to listen to as he rumbles with phlegmy, folksy conviction to defend Robinson’s right to play.

The one thing you generally can say about Harrison Ford movies is that you’re always aware you’re watching Harrison Ford. With some facial prosthetics, geeky glasses, the brims of his fedora hats flopping over his eyes and character-actor wiles we rarely see from him, Ford manages to disappear into this role.

Helgeland’s dialogue becomes preachy at times, and away from the ballfield or front office, "42" often languishes in soapiness. As Robinson’s wife, Rachel, Nicole Beharie is sweet and saintly but not very interesting. The story of black baseball writer Wendell Smith (Andre Holland) parallels Robinson’s, but the film burns up a lot of time trying to establish a camaraderie between the two that never quite gels.

Still, it’s the best work Helgeland ("Payback," "A Knight’s Tale") has done as a director (he’s had better results as a screenwriter, winning an Academy Award for "L.A. Confidential" and earning a nomination for "Mystic River").

And for all the hate and hostility it depicts, "42" is a film about decent-hearted people. Hate can be infectious, but so can decency. It’s the decency you’ll take away from "42."