A kind of feel-good movie about racism, “42” has some startlingly effective moments, especially whenever Harrison Ford is carving out what looks like a new career as a crusty character actor.

He plays Branch Rickey, the Brooklyn Dodgers general manager and civil-rights pioneer who broke the color barrier by hiring an African-American talent, Jackie Robinson, to play ball on an otherwise all-white team in the mid-1940s. It’s a fabulous part for an actor in aggressive transition.

Rickey seems happiest when he’s forcing confrontations between the vulnerable Robinson and old pros who resist Rickey’s pacifist solutions. What really motivates him is a longing for social justice that can be expressed only through extreme nonviolent resistance.

The carefully cast supporting actors include Lucas Black as Pee Wee Reese, Andre Holland as Wendell Smith and Christopher Meloni as the impassioned Leo Durocher.

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As Robinson, Chadwick Boseman, a playwright/actor who had a small role in the 2008 football movie “The Express,” is always convincing as a proud man forced to compromise at key moments. The script by writer-director Brian Helgeland (an Oscar winner for cowriting “L.A. Confidential”) is a rich source of baseball humor.

Robinson played himself in a 1950 biography that was noted for its honest approach to segregation at the time. Spike Lee attempted a 1995 remake with Denzel Washington, but the project didn’t happen until Helgeland put it together.

This may not be the last word (or film) on Robinson (or Rickey). “42” can feel incomplete (the bland music and the filmmaker’s obsession with dates and places are problematic), yet at the same time it offers a very good place to start.

John Hartl: johnhartl@yahoo.com