Singer-songwriter Martha Wainwright. (Universal Music Canada)

For years, Martha Wainwright played Linus to her older brother’s Lucy. Never bashful about his prodigious talents, the flamboyant Rufus Wainwright commanded the spotlight, wielding his gifts (a huge personality! Salacious stories! Impossibly ornate music!) like an elusive football for listeners and scribes to chase. Young Martha was more or less relegated to the shadows, clutching the security blanket of her own solid songs while singing backup for Rufus and playing the occasional solo gig.

She quietly accumulated a handful of very fine recordings, which she sold at her live shows. Wainwright took her time making the next logical step – releasing a full-length album. The delay defied logic: here was a girl with a stellar artistic pedigree (her parents are folk royals Kate McGarrigle and Loudon Wainwright III), making marketable music. Wainwright’s songs were an effervescent hybrid of folk and pop with jazz-inspired chord patterns. And yet, she couldn’t get a break.

Martha Wainwright is finally comfortable being a performer because she’s finally comfortable being a Wainwright. For a long time, she had the air of a sullen teenager about her. She wasn’t necessarily trying to prove herself worthy of the family name; she was hell-bent on proving the name didn’t mean anything.

When the Montreal-bred singer-songwriter finally signed a deal and started putting out proper releases in 2005, she still sounded tentative. Sure, there were moments of brilliance: the soaring (and controversial) anthem Bloody Mother F***king Asshole, the doo-wop-tinged When the Day Is Short, the cascading Factory, which was reminiscent of a lonely Ronette on downers. But Martha Wainwright’s self-titled debut felt a bit jarring alongside more contemporary material. And contrasted with Rufus’s astoundingly original voice, Martha’s work still came up slightly short.

But with the release of her awesomely titled second album, I Know You’re Married, But I’ve Got Feelings Too, Wainwright has made the album she’s always had in her. Released this month, it’s the work of an artist who – to dust off a fitting cliché – is ready for her close-up. So what took her so long?

“I really wasn’t pushing hard enough,” Wainwright says, swigging from a bottle of Corona, during an interview before her recent Toronto concert. In the past, she has argued that labels were loath to sign her because her music was too “arty,” but she’s more forthright now.

“I didn’t believe in myself enough. I was out singing backup with Rufus, I was doing my little shows, I was getting stoned before going on, I was showing up late to meetings,” she says with a rueful chuckle. Though she has a remarkable singing voice — a fizzy, sexy caterwaul that hiccups and explodes around her loudest notes — Wainwright’s speaking voice is closer to one of those quick-talking Girl Fridays from an old-time movie. “I was like, ‘I’m allowed to be rock ’n’ roll! That’s what I’m supposed to be!’ But in retrospect, I don’t think I believed in myself fully, which is what you have to do to succeed in anything in life.”

The cover for Martha Wainwright's new album, I Know You're Married, But I've Got Feelings Too. (Universal Music Canada)

Many artists invoke that sort of Secret-style power of positive thinking jargon as an easy out when trying to explain mismanaged careers or professional screw-ups. In Wainwright’s case, though, I buy it. Her sparkling new single You Cheated Me (the poppiest song she’s ever written) may seem to be about infidelity at first listen, but even she grants that it’s about “cheating on yourself with drugs and alcohol.” Wainwright says it took some outside encouragement to bolster her self-confidence — specifically, that of her producer, Brad Albetta, whom she married last September.

“I don’t want it to seem like this is the only reason, but you know all of [my] songs about unrequited love and loneliness?” She winces. “I always believed – and I think I still do – that I couldn’t drum up enough confidence to [be a musician] because I needed someone to tell me that it was good and that they loved me and all that stuff.

“And I guess,” she continues, sighing, “needing Brad and having him help me and not talk about my family? That was very helpful to me. I think I always thought of myself as a kind of rejected thing.” Like the black sheep of the Wainwright clan? “Yeah, a black sheep. And I think I, sadly enough, wanted to be loved.”

The relationship between a singer and a producer is a particularly intimate one — you’re trying to find a person who can replicate the sounds you hear inside your head. Wainwright and Albetta hooked up while recording her self-titled debut. She says it was initially “a very terrible relationship. Although we liked each other, we were working together, and you don’t know if that’s right. And it was kind of rock ’n’ roll. It was definitely not blissful, which was great, ’cause there was still shit to talk about. There were great songs to write,” she snorts.

Wainwright was strategic, however, in recording I Know You’re Married, But I’ve Got Feelings Too. She recruited two other big-name producers – Tore Johansson (Franz Ferdinand) and Martin Terefe (KT Tunstall) – so she could “pit [the three of] them against each other” while she held the reins. This is a woman who revels in being the boss. During her pre-show sound check in Toronto, I saw her sternly order the boys in her band back onstage to tinker with monitor levels, bickering semi-playfully with Albetta all the while.

Having all three guys on board contributed to the impressive variety on the album, which ranges from languorous piano ballads (Comin’ Tonight) to dark, knife-edged cabaret (Tower Song) to art-pop curiosities (a cover of Pink Floyd’s See Emily Play, on which the singer channels Kate Bush). Not only that, but Wainwright has reached new levels of sophistication in her lyrics. Tower Song addresses war through the neat juxtaposition of lovers entwined in Sarajevo and the rubble left in her adopted home, New York; The George Song is a blunt address to a friend who took his own life; In the Middle of the Night reflects on mortality.

Onstage, as in conversation, Wainwright is bubbly and exuberant. She’s given to swearing like a sailor – no surprise, coming from a girl who called her best-known song Bloody Mother F***ing Asshole. Her style may have its roots in a winsome folky tradition, but Wainwright has blossomed into a ballsy rock ’n’ roll frontwoman.

Wainwright performs at South By Southwest in Austin, Tex. in March 2008. (Sasha Haagensen/Getty Images)

You get the sense that Wainwright is finally comfortable being a performer because she’s finally comfortable being a Wainwright. For a long time, she had the air of a sullen teenager about her. She wasn’t necessarily trying to prove herself worthy of the family name; it’s more that she was hell-bent on proving the name didn’t mean anything. Deep down, she wanted to establish herself as an artist in her own right.

Of course, it’s hard to prevent people from talking about your family when their legacy has been mapped out in songs. Loudon Wainwright is famous for turning family dramas into song lyrics. “My father and I had an argument when I was 14, where I said – it was before I started writing songs – ‘You can’t say that because I don’t have an opportunity to say my side of things!’ And then he wrote Father-Daughter Dialogue,” Wainwright says. In that song, Loudon assumes his teenage daughter’s voice to mount a rather vicious attack on himself:

Dearest daddy with your songs

Do you hope to right your wrongs

You can’t undo what has been done

To all your daughters and your son.

The facts are in and we have found

That basically you’re not around

“You know, the guy’s honest,” Martha cackles. “Anyway, there’s a line – ‘the guy singing the songs ain’t me’ – which is about the separation between the songwriter and the person.”

Perhaps that’s what Wainwright has finally figured out: as a performer, she doesn’t have to just play herself, but rather the bigger, bolder, more assured person she wants to be. Rufus realized this instinctively; for Martha, the revelation seems to have come through a passion for the theatre (she dropped out of Concordia University’s drama program), revitalized by her collaboration with London’s Royal Ballet on a production of Kurt Weill’s Seven Deadly Sins last spring.

“I now understand vaudeville – it’s kind of real,” says Wainwright. “Like, if you allow yourself to be theatrical – and not in like a Dresden Doll way,” she grins, “but in a real way, without too much of a shtick, things can happen. You can surprise yourself.”

I Know You’re Married, But I've Got Feelings Too is in stores now.

Sarah Liss writes about the arts for CBCNews.ca.