Last year, he received rave reviews for his performance as a young Agent K opposite Will Smith in the wildly successful “Men in Black 3.” Now, Josh Brolin stars as Sgt. John O’Mara, a man who’s come back from war, and can’t quite figure out how to live in peace time, in Warner Bros.' new action-thriller “Gangster Squad.”

Also starring Sean Penn, Ryan Gosling and Emma Stone, “Gangster Squad” is a stylish retelling of events surrounding the LAPD’s efforts to take back their nascent city from one of the most dangerous mafia bosses of all time.

Due to rampant corruption in the ranks at nearly every level, Police Chief Bill Parker (Nick Nolte) is unable to unleash the full force of the LAPD on notorious mobster Mickey Cohen and his thugs, or even publicly go after them. Parker must instead rely on a furtive few to undermine the mobster’s operation. His mandate requires they execute no search warrants and make no arrests; they must anonymously, ruthlessly and with as much efficiency as possible, cut out the heart of Cohen’s livelihood, by any means necessary. They are not to bring him to justice. They are to bring justice to him.

To head up this clandestine crew, Parker chooses a man who has no trouble taking matters into his own hands – Sgt. John O'Mara. “I’m a seventh generation Californian and a native of Los Angeles, so I have massive pride about my hometown,” Brolin states. “I felt a real connection with O’Mara for that reason. I also liked that while he doesn’t heed all the rules and he doesn’t like red tape, he has strong principles; he sees the wrongs that need to be righted and he believes he can turn things around.”

“O’Mara is a very principled person who’s returned home after America’s victory over the Nazis,” director Robert Fleischer says. “He doesn’t like that another form of evil has taken up residence in his city and corrupted it with gambling, prostitution and drugs. He can’t abide it. So, he accepts Parker’s challenge, even though it means putting his and his family’s lives on the line.”

Producer Kevin McCormick observes, “He really feels it’s his obligation to make the world a better place, but he sees that others don’t necessarily hold to the same standard. He doesn’t really fit in because he won’t bend to accommodate injustice. He’s extremely rigid, which could be seen as a character flaw or as what sets him apart, what makes him special, which is what Parker sees.”

Though he is one of many cops on the force, O’Mara prefers to operate on his own, and in his own way. He’s something of a renegade who does things singlehandedly, sometimes even unarmed. “The script described O’Mara as having a chin so strong you could break your fist on it,” Fleischer recalls. “When you look at Josh, he lives up to that; he looks like he stepped out of that time period, and plays the part with a measured, quiet stoicism that’s really powerful.”

To take out Cohen, O’Mara will have to work closely with a team, and the chief charges him with pulling together the roster. “He recruits a bunch of misfits like himself,” says Brolin, “guys in lowly or outsider positions because of their rebellious natures, but who are able to get the job done, sometimes in a very brutal way.” Thus, the Gangster Squad is born.

Opening across the Philippines on Jan. 30, “Gangster Squad” is distributed by Warner Bros. Pictures, a Warner Bros. Entertainment Company.