You know Stephen Root. He’s that one guy. That actor who plays that weird dude in that one thing. Or, rather, more than 200 things. He’s the slob with the red stapler, the eccentric billionaire, the blind Mississippi D.J. He is a walking paradox: You know his face, but that’s largely because he has so effectively transformed himself over and over.

He is also, thanks to his supporting role playing the sleazy Monroe Fuches on HBO’s dark comedy series “Barry,” an Emmy nominee.

In a TV and film career spanning more than three decades, Root, 67, has been one of Hollywood’s most prolific and versatile character actors, known for playing strange and memorable characters like Milton in “Office Space” and for his oddball roles in multiple Coen Brothers movies. His character in “Barry” is similarly singular: A kind of talent manager for an assassin (played by Bill Hader), Fuches is detestable and hilarious, pathetic and somehow lovable — despite making a living by having people murdered.

Fuches is also Root’s first regular role on a TV series since he played the eccentric billionaire Jimmy James in the ’90s NBC sitcom “NewsRadio.” In a sit-down interview last week at the historic Pete’s Tavern in downtown Manhattan, he said that the choice to avoid long-term TV gigs had been by design: Fighting typecasting, he simply hadn’t wanted “to be locked down.”