LOS ANGELES -- Josh Brolin says he wasn't interested in politically themed TV series in the past. But he signed on as star of NBC's new "Mister Sterling" because he thinks network television, prodded by the success of more daring fare on cable, is finally taking "bigger risks."

And he's pushing the show to keep taking bigger ones.

Brolin said he was impressed with series creator and executive producer Lawrence O'Donnell Jr., an Emmy-winning producer of "The West Wing" and a political analyst for MSNBC.

"I liked his dichotomous nature -- very smart, but very kind of angry," the actor said.

Brolin's character, freshman Sen. Bill Sterling Jr., is an independent, not easily drawn to either side of the political spectrum. He bucks many of the Senate's procedures and traditions.

"I never saw myself doing something political," Brolin says. But the behavior of politicos does intrigue him: "it's so mysterious, so hidden, so behind closed doors."

"Mister Sterling" took over NBC's Friday 7 p.m. time slot, previously occupied by "Providence."

Brolin's character is evolving, although maybe not in the direction he expected.

"I think there's an arrogance to him that I'm just starting to understand, that I didn't see before, that I'm not sure if I like," he said. "His intention is in the right place, but I think he has this thing that 'if everybody would do things more my way it would be better."'

Brolin hopes the show will expose more of the man's personal side.

"Heroics are great, but I think it's monotonous," he said. "After a while I don't think you can sustain just heroics. I think the greatest part about watching something like Superman is that there's kryptonite."

He also would like to see more basic humor, and a little rougher language.

All of this is said in a way that sounds constructive rather than complaining, and O'Donnell is clearly open to Brolin's ideas.

"He really can't make a false choice in this role now. He really owns it," said O'Donnell. When Brolin asks how he should do something, "I just tell him, 'Whatever you choose is right. It's your character now."'

The 35-year-old Brolin, son of actor James Brolin, didn't plan to follow his father into acting. "I really had a distaste for it," he says, recalling his dismay watching his dad work with egotistical stars who made it "all about themselves."

But at Santa Barbara High School, Josh improvised a character in acting class -- "balding, middle-aged, very overweight ... breathing kind of hard." He realized acting was fun.

He studied with the late acting coach Stella Adler. For five years he worked at the Reflections Festival in Rochester, N.Y., in partnership with Anthony Zerbe, with whom he starred in the 1989 TV series "The Young Riders." He also starred on Broadway in Sam Shepard's "True West."

His movies include "Goonies," "The Mod Squad" and "Hollow Man."