An obsequious, Southern-twanged Atlanta transplant with a thrift-shop wardrobe, Deputy Chief Johnson believes emotional insight has a singular function: as a tool to break perps in the interrogation room.
At that, she is an unparalleled master. Real life is another story. A mystery story.
Why do her parents intimidate her? Why won't she commit to her dreamy FBI boyfriend (Jon Tenney)? Why can't she give up Ring Dings?
Sedgwick sees right through her.
"Most people live on the surface of life. It's easier, frankly. It's harder to be a truth-seeker, to want to change things about yourself. That's exhausting. Brenda has no time or interest. She wants to analyze everybody else."
Despite her aversion to introspection, Deputy Chief Johnson will be faced with at least one trauma this season that forces the crime-solving savant to search for clues to her own M.O.
She suffers "an unusual health crisis," says creator and executive producer James Duff, trying to avoid details. "It's an issue a lot of women face. She has to learn how to do that and maintain her job and her relationship."
Ever the good cop, Sedgwick puts it more obliquely.
"An element comes into her life unexpectedly that makes her come to terms with some things she wasn't ready or willing to come to terms with."
She must also come to terms with her father, a gruff retired military officer who suddenly shows up on the Aug. 20 episode. Northern Exposure alum Barry Corbin will do a four-episode arc. Frances Sternhagen returns as Johnson's mother.
Sedgwick, 41, and Duff, 51, both understand why many adult children are tense around their parents.
"We all have a certain fear of disappointing them; a fear that they won't be happy with the person we turn out to be," Sedgwick says. "We all want their approval."
Growing up in New York, Sedgwick had no trouble figuring out how to shine on the home front. "My mother thought the greatest people in the world were artists, especially actors," she says. "Her face lit up when she talked about great acting. It wasn't lost on me."
Sedgwick acknowledges she's ambivalent about her own kids' pursuing acting as a career.
Daughter Sosi, 15, and college-bound son Travis, 18, both appeared in 2005's Loverboy, directed by Kevin Bacon, her husband of almost 20 years. Sedgwick was star and coproducer.
"It's an incredibly narcissistic, insecure profession," she says. "It's always about you and your feelings. There's a lot of rejection. . . . If they can, I'd like them to do other things.
"But if it's in their soul, and there's no way they could do anything else, I would support them 100 percent. No one could have said anything to me that would have made me not want to be an actor."
From the beginning, Duff envisioned Closer's lead as female. He likes writing for women and says being gay gives him more insight into their characters.
"Women are outsiders in the world of authority. I understand that. I never felt like an insider. I've never been interested in being an insider."
When Duff came out to his parents, in 1976, "they sent me to a shrink for 18 months. It was not the sort of thing that Southern Baptist Texas boys were supposed to do." He and his partner, actor Phillip Keene, have been together almost 15 years.
Duff, based in L.A., was convinced he didn't have a prayer of signing Sedgwick, a committed New Yorker and film star.
"When her name came up, I thought, 'Please, we're in a hurry. I have no time for fantasies,' " Duff recalls. "She had already said on the record that she didn't want to leave New York or do TV."
Ignoring him, the casting director sent a script to her agent and manager anyway. Despite their recommendations, she refused to read it.
"I told them not to send it to me," Sedgwick says. "I didn't want to be in L.A. six months a year." When she finally picked it up, she was hooked. Duff "was absolutely stunned."
So was the audience. Closer averaged 5.5 million viewers its inaugural season, increasing to almost 6.7 million last season.
Duff swears he has "absolutely no idea" why his show is a success.
"We just happened to be standing where the wave came. We were ready to ride it. You can be surfing all day long, and nothing happens. There are a lot of good shows that get on the air and disappear."
The Closer won't be one of them. Case closed.
Contact TV columnist Gail Shister at 215-854-2224 or email@example.com. Read her recent work at http://go.philly.com/gailshister.