“Brave” is a word sorely overused by critics when describing any actor taking on a somewhat sexualized character – especially when they take off their clothing in the process. If the sexuality in question is LGBT, so much the “braver,” apparently. It's a word, then, that you may have read applied a few times to Robin Weigert's terrific performance as a dissatisfied lesbian wife and mother in Stacie Passon's sharp, sensual debut feature “Concussion” – released last Friday on the Weinsteins' TWC-Radius label.

Among its many individual merits as a witty, pointed study of normalized alternative families and the long-haul challenges of homosexual domestic bliss, “Concussion” also delights as an overdue leading-lady showcase for Weigert – the warm but tough-as-nails character actress whose strongest career opportunities to date have been on the small screen. She received in Emmy nomination in 2004 for her vitally vulgar Calamity Jane in cult Western series “Deadwood,” and is regularly featured in the hit biker drama “Sons of Anarchy.”

Until now, Weigert's most generous film opportunity came in Steven Soderbergh's odd stylistic experiment “The Good German.” That has now been handily bettered by complex, prickly role in “Concussion” as Abby, a woman who handles the combination of familiar suburban ennui and spousal indifference in a rather unexpected fashion: she takes up a secret occupation as a high-end call girl in New York City, serving other women with unfulfilled sexual needs.

The character has stoked controversy since the film's divisive Sundance debut, but Weigert plays her with weary good humor, casually blossoming as Abby grows more comfortable in her imperfect skin. If it is indeed a brave performance, it's not self-consciously so.

“I don't really know how I respond to that word,” Weigert says breezily on the phone from New York, where she's spending a few days before heading to Nebraska to complete work on a “beautifully surprising” film project. “I mean, yeah, it does put you out there, literally and figuratively, when you are playing a character who has a lot of sex on screen. I don't know that it matters what type of sex. I think when I feel fear, that's often a cue that I should do something. If I begin to feel fear, that's a strong sign, psychologically, that something has its hooks in me somewhere deep. That's why we do it.”

A large part of Weigert's fear didn't stem simply from her character, but the prospect of taking on such sensitive material with a first-time feature director. Weigert didn't pursue or even audition for the role; instead, she was somewhat bemused when Passon approached her out of the blue.

“For whatever reason, Stacie saw me as this character,” Weigert says. Even now, she still sounds surprised. “I don't know what in my previous work suggested this role to her, because I have done a lot of character parts and I don't see anything in my body of work that exactly resembles this character, but she somehow Abby in me. That was my great fortune.”

Flattered as she was, Weigert admits to having some reservations before finally taking on the role. “I might have backed away from it, if it hadn't so taken hold of my imagination,” she says. “It scared me, because I couldn't really look to seven other movies Stacie had made and say, 'Okay, I know what this will be.' It felt like it could turn out to be anything. But something about this journey of a woman back into her body, from a dissociated state back into something that she had probably left for dead – that spoke to me.”

Once on board, however, Weigert got actively involved in the project beyond her own remit as a performer – recruiting a number of friends and colleagues to join her on the challenging endeavor. Most notable among them is her “Sons of Anarchy” co-star Maggie Siff, who shines in tangy supporting role as one of Abby's most unlikely clients.

“Once I was in, I was determined that it needed to be of good quality, that the cast was full of people I could rely on,” says Weigert. “That made me feel more secure. But once you've committed, you just go blind, and you go all the way, and then you hope. Because there really isn't any kind of guarantee that it's going to work.”

Guy Lodge is a South African-born critic and sometime screenwriter. In addition to his work at In Contention, he is a freelance contributor to Variety, Time Out, Empire and The Guardian. He lives well beyond his means in London.