Troy Garity has identified four pillars of American life: the Government, the People, People with Money and the Press.

At least this theory serves him nicely on his Starz drama series Boss, where Garity plays a newspaper editor who locks horns with the towering title character, Chicago Mayor Tom Kane ( Kelsey Grammer).

Garity relishes his role as Sam Miller.

“I’m a good source of agitation and conflict with our hero, the evil mayor,” he tells The Associated Press. “I’m actually doing the right thing, but I’m vilified by the audience because I’m trying to take down the person the audience is rooting for.”

In short, Sam Miller has a worthy adversary. As Boss began its second season Friday, Kane remains a titanic figure of charm, defiance and corruption. But at the same time human frailties haunt him, mostly in the form of a degenerative brain disease he hides from the world.

As for Grammer, he “is so professional and, considering how dark the show is, so light and giving!” Garity gushes.

As it happens, Garity has firsthand knowledge of the political world and the glare of the press that inform Boss. Though he bears the surname of his paternal grandmother, his mother is Jane Fonda, the actress, political activist and lifelong lightning-rod for the right. His father is Tom Hayden – activist, former California state senator and one-time member of the Chicago Eight.

“My father thinks I’m playing HIM,” laughs Garity. “He says, ‘You look like me, and I was going after the mayor of Chicago, too.’ ” Indeed, Hayden’s leadership role in the 1968 protests in Chicago – a city then ruled by Mayor Richard Daley – was depicted in the biopic Steal This Movie, in which Garity played his own dad.

Besides his mother, the Fonda acting dynasty that Garity belongs to also includes his uncle Peter and cousin Bridget. The patriarch, of course, was Henry Fonda. But Garity says he didn’t know his grandfather as one of Hollywood’s most enduring and beloved actors, but instead as a painter who inspired him.

“When I’d hang out with him as a child, he’d often be in a room painting or drawing,” says Garity, 39. “That spoke to me more than acting, because I was quiet and awkward and a bit shy – and also because of who my parents were.”

Garity has had roles in Barry Levinson’s Bandits, Danny Boyle’s Sunshine, and perhaps most notably in Barbershop and its sequel. Last season he appeared on the NBC drama The Playboy Club, shot at the Chicago studio where Boss is filmed. His next feature is Gangster Squad, with Emma Stone, Ryan Gosling and Sean Penn.

The only way is up.

“I can disappear into things very easily,” Garity says. “But with acting, you have to be in the moment, and it gives me this incredibly fulfilling emotion: being really present.”